What is a membrane in a cell. What is a “membrane” and what is it used with?

The development of innovative technologies has also affected fabrics, so the question of what a membrane in clothing is and what it is intended for is becoming increasingly relevant. It is one of the multifunctional canvases in the modern range. This material is semi-permeable and is presented in the form of a film with a special structure.

Clothing and shoes made of membrane are able to repel moisture from the outside and evaporate it from the inside. This material is quite soft on the bottom, and harder on the top, as it is protective and wear-resistant. The middle layer is the membrane and protective matter.

Caring parents often ask questions about the membrane in clothes for children: what is it, is it dangerous and is it worth buying? The answers to all these questions can be found in our article. This material is actively used to create various elements of both children's and adult clothing, so this information will definitely be useful to everyone.

Properties

Knowing that the membrane in clothing is a synthetic material, many people want to know its properties. They will help determine its purpose and necessity for modern society. The membrane structure is characterized by:

1. Waterproof. This parameter is presented in digital form. It denotes the water pressure that the matter can withstand. When choosing a specific product, you must pay attention to this. Clothing and shoes marked 3000 can withstand only light rain, material with a rating of 10,000 can overcome heavy rain, but a rating of 20,000 guarantees the product is waterproof even in stormy conditions.
2. Wind protection. Regardless of the waterproof rating, any item of clothing will protect its owner from the wind. Membrane products will never allow people to get cold.
3. Vapor release. The third criterion is also of particular importance and is also presented in number format. It indicates the amount of steam in a certain area (g/m2) that comes out during the day. The quality of the material depends on this criterion - the higher it is, the better the material.

Reviews about membrane clothing are always positive. This is largely due to its capabilities described above. It is thanks to them that clothes and shoes made from such fabric are popular in different countries among people of all ages.

Varieties

Winter membrane clothing is available in various variations for both adults and children. Today there are the following types of matter:

1. Two-layer. They are produced using a unique technology, the essence of which is that the membrane is glued to the inside of ordinary fabric, and on top of it there is a reliable protective lining.
2. Three-layer. These options represent the basis of the membrane itself and the knitted mesh. The layers are fastened together using lamination. The lining in this case acts as a mesh. This technology makes it possible to reduce the weight of the finished product.
3. Double layer with knitted lining. The design of this material is quite similar to the previous one. The only difference is that the usual lining is replaced with foam jersey. Clothing of this type has even less weight, but this does not change its properties in any way.

Compound

To better understand what a membrane in clothing is, its composition will help. Modern fabrics are made from the following materials:

1. Polyester. This element can hold its shape perfectly. It is quite pleasant to the body. Consumers love it for its long service life and high strength indicators.
2. Tencel. Everyone knows this material due to its softness and ability to absorb moisture. It is obtained from eucalyptus wood.
3. Cotton. It is an important element in membrane clothing. This material is soft to the touch, it absorbs all moisture and retains heat.
4. Bamboo. This fabric is distinguished by its high strength and hypoallergenicity. Bamboo is able to retain sunlight and eliminate unpleasant odors.
5. Teflon. This material has micropores on the outside. It does not let water through. The only drawback of Teflon is the possibility of clogging pores, which interferes with the process of moisture evaporation.
6. Polyurethane. In this case, there are no pores on the surface, but the material still does not allow moisture to pass through. All liquid penetrating inside accumulates from the inside and then evaporates. Among the disadvantages is the fact that it will take a long time to eliminate water.
7. Combined matter. The inner part has a foam membrane, on top of which there is a protective layer that prevents the pores from clogging. The combined material has all the advantages of Teflon and polyurethane.

It is due to these components that all adult and children's outer membrane clothing can be safely used in inclement weather. The material will provide warmth and dryness under any conditions.

Usage

Outer membrane clothing is now made for both adults and children. As a rule, these are workwear made from high-quality nylon or dense polyester. In addition, this fabric has proven itself well in sewing moisture-resistant suits.

Athletes who go to competitions outside their country in the winter or autumn know that membrane clothing is the best option for them. Today, the production of costumes specifically for such people is carried out by:

• TransActive;
• Porelle;
• Ultimex;
• Cyclone.

At the same time, the fabric is in greatest demand in the following areas:

• mountaineering;
• mountain and ski tourism;
• trips;
• fishing;
• leisure;
• hunting;
• any winter types of sports.

Price

Having learned what a membrane in clothing is, many people want to purchase it. The average cost of material is 400 rubles per meter. But this amount is determined not only by the type of material, but also by its manufacturer, so some products can cost customers 3-4 times more.

In this regard, there are only positive reviews about the membrane (clothing) for children and adults. For some, this price may indeed seem high, but in fact the quality and capabilities of the product justify it. Therefore, buyers have no complaints about the clothes and the fabric itself.

Advantages and disadvantages

Sports membrane clothing has certain features that you need to know about before purchasing it. Like any material, the membrane has its own advantages and disadvantages, for which customers may like it or, conversely, repel them.

Among the positive qualities the following points can be highlighted:

• lightness and comfort (both children's and adult suits allow a person to move freely without constraining him or limiting him);
• no need for an additional layer of warm clothing (this nuance is especially important for small children, since if they have several sweaters they always feel discomfort);
• ease of washing and cleaning (membrane fabric is quickly cleaned of any contaminants and does not require the purchase of any special expensive products).

The disadvantages include:

• fragility (this nuance depends on the category of fabric);
• the need to choose the right bottom layer (you will have to spend a lot of time on this if you initially had no idea about clothing).

Membrane fabric is not intended for heating, but it perfectly reduces the sweating of its owner and does not allow the body to cool down. For sedentary children, it is best to purchase winter suits with a special insulating lining. At the same time, it is worth paying attention to the fact that membrane clothing is not entirely suitable for daily wear, since its purpose is only for some situations already described above (mountaineering, mountain recreation, tourism, and so on).

What to wear under these clothes

Having understood what a membrane in clothing is, you should decide on the wardrobe items that need to be worn under it. In the winter season, it is imperative to follow the correct principle of selecting layers. It will help protect the body from overheating and a sharp reaction to temperature changes. It is necessary to remember that the membrane material breathes well, which completely eliminates sweating.

Most often, people dress in three layers:

• internal (underwear);
• medium (regular attire - jacket, trousers);
• outer one (the winter membrane suit itself, protecting from the wind).

Wash

Children's winter clothing made from membrane requires proper care to maintain its strength. It is not recommended to wash it with detergent, as it will simply clog the pores and they will not allow fresh air to pass through. The list of these products includes various rinses, conditioners, powders, and so on.

You can wash clothes with laundry or liquid soap. During the washing period, the material remains safe and sound, but dirt may remain in the pores. The properties of the membrane will not change if it is cleaned in this way. But even despite this, it is better to wear outerwear carefully, avoiding heavy stains.

Cleaning dirt from clothes using a washing machine is strictly prohibited. It does not have a very good effect on the coating, because it works by soaking and then spinning. The best method for dealing with stains on membrane clothing is hand washing. The ideal water temperature for this will be 30-40 degrees.

Before starting the procedure, you need to connect the sleeves of the jacket and fasten all the rivets and fasteners located on it. After washing, you should not wring out the item, since to speed up its drying it will be enough just to blot the fabric with some absorbent rag. It should be remembered that the drying process must be carried out on a horizontal surface.

Special care

Membrane children's clothing for the winter should never be ironed after washing. This does not depend on the season, since the item can deteriorate in appearance at any time at elevated temperatures. The water-repellent properties of the membrane can be restored using a special spray containing fluorine. Thanks to this product, a reliable film is formed on the surface of the clothing, which will protect and reduce the negative effects of ultraviolet rays.

Storage

On days when membrane clothing is not in use, it must be stored on a hanger. It should always be in an upright position. To protect it from clogging the porous structure, you need to put a plastic cover on top. You also need to remember that such clothes cannot be stored crumpled and wet. Therefore, before putting things in the closet, they need to be thoroughly washed in accordance with the rules described above and dried.

Manufacturers

Today, Gore-TeX is especially popular. It is engaged in the production of membrane clothing. Initially, the brand produced equipment intended for astronauts, but a little later it offered high-quality sets for mountain tourists, skiers and mountaineering enthusiasts.

Based on quality criteria, you can compare the products of Triple-Point, ULTREX, Sympatex. These products are distinguished by high-quality material, which comes in various modifications. Their cost, of course, is high, but it fully corresponds to the capabilities of the products.

Ceplex and Fine-Tex membrane items are available to many consumers. They are designed for only two seasons, but only if they are actively used. After this period, the material gradually begins to let in moisture, which will no longer be possible to correct.

When choosing a particular membrane product, you should definitely pay attention to the information about gluing seams. It is indicated on each item of clothing. In most products, absolutely all seams are taped, but there may be some where only the main ones are properly processed. For people who engage in active sports, it is best to choose clothes where all seams will be securely reinforced.

Shoes

Special membrane shoes are intended only for professional athletes and people who prefer active recreation outside the city. But despite this, in modern times it is used in everyday life. Warm, fairly light in weight and moisture-resistant shoes are an excellent option not only for the rainy off-season, but also for the harsh winter. Decent air circulation helps maintain a comfortable microclimate inside, as well as maintain optimal foot temperature for a long time.

A distinctive feature of membrane shoes, like clothing, is the presence of a high-tech polymer material with small pores. It is secured quite tightly between the top padding and the inner lining. The minimum size of the holes in this intermediate layer does not let moisture in and does an excellent job of removing natural vapors. From this we can conclude that shoes made of membrane provide good air circulation and maintain optimal dryness and warmth of feet in all weather conditions.

How to maintain the condition of your shoes

Any shoes, including membrane ones, require proper care. It will help maintain its beautiful appearance and thermoregulating properties, as well as extend its service life. This item of clothing needs to be dried only at room temperature, but under no circumstances should you use heating devices, as they will quickly damage the integrity of the structure. In this case, it is best to remove the insole first.

As soon as necessary, shoes should be cleaned of dust and dirt. If the surface is made of leather, then it is better to wipe it with a soft cloth; for nubuck, a special brush is more suitable, but to clean textiles, you can use a sponge. Too much soiled shoes can be washed with a soap solution or some water-based product, but without fats and oils in the composition.

You should regularly apply compounds to your shoes that will repel moisture. They will protect the material and increase its service life, maintaining its original appearance.

It's no secret that all living beings on our planet are made up of cells, these countless "" organic matter. The cells, in turn, are surrounded by a special protective shell - a membrane, which plays a very important role in the life of the cell, and the functions of the cell membrane are not limited to just protecting the cell, but represent a complex mechanism involved in the reproduction, nutrition, and regeneration of the cell.

What is a cell membrane

The word “membrane” itself is translated from Latin as “film,” although a membrane is not just a kind of film in which a cell is wrapped, but a combination of two films connected to each other and having different properties. In fact, the cell membrane is a three-layer lipoprotein (fat-protein) membrane that separates each cell from neighboring cells and the environment, and carries out controlled exchange between cells and the environment, this is the academic definition of what a cell membrane is.

The importance of the membrane is simply enormous, because it not only separates one cell from another, but also ensures the cell’s interaction with both other cells and the environment.

History of cell membrane research

An important contribution to the study of the cell membrane was made by two German scientists Gorter and Grendel back in 1925. It was then that they managed to conduct a complex biological experiment on red blood cells - erythrocytes, during which scientists obtained the so-called “shadows”, empty shells of erythrocytes, which they stacked in one stack and measured the surface area, and also calculated the amount of lipids in them. Based on the amount of lipids obtained, scientists came to the conclusion that they are just enough to cover the double layer of the cell membrane.

In 1935, another pair of cell membrane researchers, this time Americans Daniel and Dawson, after a series of long experiments, established the protein content in the cell membrane. There was no other way to explain why the membrane had such a high surface tension. Scientists have cleverly presented a model of a cell membrane in the form of a sandwich, in which the role of bread is played by homogeneous lipid-protein layers, and between them, instead of oil, there is emptiness.

In 1950, with the advent of electronics, the theory of Daniel and Dawson was confirmed by practical observations - in micrographs of the cell membrane, layers of lipid and protein heads and also the empty space between them were clearly visible.

In 1960, the American biologist J. Robertson developed a theory about the three-layer structure of cell membranes, which for a long time was considered the only true one, but with the further development of science, doubts began to arise about its infallibility. So, for example, from the point of view, it would be difficult and labor-intensive for cells to transport the necessary nutrients through the entire “sandwich”

And only in 1972, American biologists S. Singer and G. Nicholson were able to explain the inconsistencies in Robertson’s theory using a new fluid-mosaic model of the cell membrane. In particular, they found that the cell membrane is not homogeneous in its composition, moreover, it is asymmetrical and filled with liquid. In addition, cells are in constant motion. And the notorious proteins that make up the cell membrane have different structures and functions.

Properties and functions of the cell membrane

Now let's look at what functions the cell membrane performs:

The barrier function of the cell membrane is the membrane as a real border guard, standing guard over the boundaries of the cell, delaying and not allowing harmful or simply inappropriate molecules to pass through.

Transport function of the cell membrane - the membrane is not only a border guard at the cell gate, but also a kind of customs checkpoint; useful substances are constantly exchanged with other cells and the environment through it.

Matrix function - it is the cell membrane that determines the location relative to each other and regulates the interaction between them.

Mechanical function - is responsible for limiting one cell from another and, in parallel, for correctly connecting cells to each other, for forming them into a homogeneous tissue.

The protective function of the cell membrane is the basis for building the cell's protective shield. In nature, an example of this function can be hard wood, a dense peel, a protective shell, all due to the protective function of the membrane.

Enzymatic function is another important function performed by certain proteins in the cell. For example, thanks to this function, the synthesis of digestive enzymes occurs in the intestinal epithelium.

Also, in addition to all this, cellular exchange occurs through the cell membrane, which can take place in three different reactions:

• Phagocytosis is a cellular exchange in which membrane-embedded phagocyte cells capture and digest various nutrients.
• Pinocytosis is the process of capture by the cell membrane of liquid molecules in contact with it. To do this, special tendrils are formed on the surface of the membrane, which seem to surround a drop of liquid, forming a bubble, which is subsequently “swallowed” by the membrane.
• Exocytosis is a reverse process when a cell releases a secretory functional fluid to the surface through the membrane.

Structure of the cell membrane

There are three classes of lipids in the cell membrane:

• phospholipids (which are a combination of fats and),
• glycolipids (a combination of fats and carbohydrates),
• cholesterol.

Phospholipids and glycolipids, in turn, consist of a hydrophilic head, into which two long hydrophobic tails extend. Cholesterol occupies the space between these tails, preventing them from bending; all this, in some cases, makes the membrane of certain cells very rigid. In addition to all this, cholesterol molecules organize the structure of the cell membrane.

But be that as it may, the most important part of the structure of the cell membrane is protein, or rather different proteins that play different important roles. Despite the diversity of proteins contained in the membrane, there is something that unites them - annular lipids are located around all membrane proteins. Annular lipids are special structured fats that serve as a kind of protective shell for proteins, without which they simply would not work.

The structure of the cell membrane has three layers: the basis of the cell membrane is a homogeneous liquid bilipid layer. Proteins cover it on both sides like a mosaic. It is proteins, in addition to the functions described above, that also play the role of peculiar channels through which substances that are unable to penetrate through the liquid layer of the membrane pass through the membrane. These include, for example, potassium and sodium ions; for their penetration through the membrane, nature provides special ion channels in cell membranes. In other words, proteins ensure the permeability of cell membranes.

If we look at the cell membrane through a microscope, we will see a layer of lipids formed by small spherical molecules on which proteins swim as if on the sea. Now you know what substances make up the cell membrane.

Cell membrane video

And finally, an educational video about the cell membrane.

This article is available in English - .

Membrane fabric is an innovative material with selective permeability. Has increased protective properties. It is used for the production of children's and sportswear, equipment for fans of active winter recreation, and representatives of extreme professions.

Why are membrane fabrics needed?

The word "membrane" has ancient origins and means "membrane". In ancient times it was used in everyday and biological senses. As science developed, the term acquired physical, chemical, and technical meaning. Now membrane technologies are used in light industry for the production of clothing.

One of the main functions of clothing is protective. Previously, rubber shoes, plastic raincoats, and other capes were used to protect against rain. These materials protected well from rain, snow, and wind for some period of time. It is impossible to stay in waterproof products made using old technologies for a long time.

On average, the human body releases more than half a liter of moisture per day, which accumulates on clothes from the inside if there is no way out. With active movements, the volume of sweat released can reach one and a half liters.

The introduction of membranes into the composition of protective fabrics allows water vapor to be removed while preventing moisture, wind, rain, and snow from getting inside.

Structure and mechanism of action of membranes

The simplest example of a membrane product is a cellophane bag (not to be confused with a plastic bag). If, for example, you pour a salted protein solution into a plastic bag and hang it in a container with clean water, then after a while the salt will penetrate through the pores of the cellophane into the water. Cellophane selectively allows small molecules to pass out, retains large ones inside, and water molecules from outside do not leak into the bag.

The membrane layer in tissues works in a similar way. It allows small molecules to come out without letting anything in.

Membranes used in light industry are usually divided into porous (containing pores) and non-porous (supposedly not containing pores). This division is arbitrary, but widespread. It is advisable to use it.

• Membranes with pores are thin polymer layers with very small holes through which molecules of gaseous water (steam) can leak from the inside, but drops cannot fit there. Let us remind you of the school course: in a drop, water molecules “stick together” - they are in the form of associated groups. In the vapor state, water molecules are lonely, the distance between them does not allow them to unite. The American company Gore-TeX makes membrane fabrics from Teflon, per 1 cm 2 of which there are about one and a half billion microholes - pores.
• Non-porous membranes act differently. They also contain many microcells with complex, sinuous shapes that resemble the structure of a sponge. Steam from the skin is absorbed into the cells, saturates the membrane, turns into condensed moisture and, due to the difference in partial pressure (this concept is also from school courses), is released out. This principle of release is possible because there is more vapor inside than outside. If, hypothetically, the owner of the clothes wears them into a sauna or other room with very high humidity, moisture will enter in the same way.

In some materials, different membranes are combined, a layer without pores is placed on the outside, and a layer on the inside with pores. The fabric is effective, but expensive.

Comparison of terms of use

• All membrane tissues remove vapors from an area of ​​high pressure to a zone of low pressure (as experts in the value gradient say).
• At high humidity, membranes with pores remove vapors better, especially if there is ventilation on the clothes. Poreless membranes are effective in relatively dry air environments. If the humidity is high or the ventilation is open, such a membrane will not work well.
• At low temperatures, a membrane with pores works better. At subzero material temperatures, poreless membranes simply freeze.
• The porous membrane can become clogged if not properly cared for or worn. Poreless membrane fabrics are durable and last a long time.

Main characteristics

Membrane fabrics are designed to protect against bad weather and create a sense of comfort for wearers. Functions justify the importance of key indicators.

• Waterproof. At high pressures in the water column, any fabric will begin to leak. Maximum tolerable exposure values ​​are important for successful operation. Clothing intended for harsh conditions must withstand pressures of 20,000 mm water column and above. A value of 10,000 mm is acceptable for normal rainy weather conditions.
• Vapor permeability characterizes the mass of vapor in grams that 1 m2 of material can release in a given unit of time (usually 24 hours). The often found minimum vapor permeability is 3000 g/m2, the maximum is from 10000 g/m2. This property is sometimes assessed by its ability to resist steam transport (RET). If this indicator is 0, the fabric completely transmits all steam; with a value of 30, the passage of steam is practically eliminated.

The membrane does not perform insulating functions. It protects from rain, wind, snow, provides “breathing” to the body, and helps provide thermal comfort.

Fabric structure

Structurally, membrane fabrics differ in design.

• In two-layer fabrics, the membrane is fixed on the inside of the fabric. Additionally, it is covered with a lining that protects it from damage and clogging.
• In three-layer fabrics, the outer layer, membrane, and inner mesh are glued together. There is no need for a lining layer. The material is very comfortable, it costs more.
• In some modifications, a special protective coating is sprayed onto the inner surface of the two-layer fabric.
• There are types of membrane fabrics with a water-repellent layer (DWR) applied on top. The coating may wash off over time. It is easily restored using special means.

Leading manufacturers

The most authoritative, historically the first company producing membrane fabrics is Gore-TeX. She made clothes for astronauts. Then several types of products were offered to skiers, climbers, and mountain tourists.

Clothing with Triple-Point, Sympatex, ULTREX membranes is comparable in quality. The material is good quality and is available in several modifications. The price is high, consistent with the properties of the products.

Products with Ceplex and Fine-Tex membranes have an affordable price. It is designed for a maximum of 2 seasons of active wear, after which the material may begin to leak a little water.

When buying clothes made from membrane fabrics, pay attention to the information about taping seams. In some varieties, absolutely all seams are taped, in others - only the main ones. For wearing in the city, taping the main seams is enough. For active sports, it may be better to choose products with all reinforced seams. The choice is up to the potential owner of the clothing.

Rules for caring for membrane tissues

The material is specific in composition and structure. Conventional washing techniques should not be applied to this group of products.

• You can wash fabric with a membrane layer in a machine using a gentle cycle and mild special products.
• You can't do push-ups in the car.
• Cannot be dry cleaned.
• There is no need to iron, there is no need to do this.
• Can be washed by hand if desired.
• You can leave the item in an arbitrarily straightened state so that water drains from it.
• The fabric gets dirty very little. After wearing and drying, it can be lightly cleaned with a regular brush.

Fabrics with membrane materials allow you to feel protected in any bad weather during the most active activities.

If you see a child on the street in a thin-looking jacket and light boots in spring changeable weather, do not rush to blame the parents for inattention to the child’s health or for wanting to toughen him up to the level of a walrus. Most likely, he is wearing membrane shoes and clothes that allow him to feel warm and comfortable in the coldest weather, without turning the child into a head of cabbage.

Why has membrane technology in the manufacture of children's clothing and shoes captivated parents all over the world? Let's find out!

1.What is a membrane and why is it needed?

Membrane technologies in the manufacture of clothing and footwear were initially used in sports, where it was necessary to ensure lightness, comfort and breathability of equipment for athletes. Later, these technologies began to be used for everyday clothing for children and adults.

The membrane is a porous material placed between the outer and inner layers of shoes or clothing. The pores of the membrane are so small that they do not allow moisture, cold or wind to penetrate inside, and at the same time make it possible to remove moisture in the form of steam when sweating. Thus, under membrane clothing a microclimate that is comfortable for the body is created, combining protection from external factors and constant air exchange.

High-quality membrane clothing and shoes are made using well-known membranes patented by manufacturers (Gore-Tex®, SympaTex®), and manufacturers of children's membrane clothing use their own developments and technologies. For example, the Skandia brand uses Skandiatex membrane material, and Alyaska uses Antex & Alaskatex.

Membrane clothing and shoes are multi-layered items in which, in addition to the membrane, additional internal and external layers provide protection from external factors. For example, the outer layer is usually impregnated with a water-repellent compound or laminated with special products, and the inner layers combine natural (for example, wool) and synthetic fibers for comfort and durability in wear.

In addition, manufacturers usually take care of such little things as the presence of reflective details on children's membrane clothing, sew in child-safe zippers that will not press the skin when fastened, and provide additional protection for the sleeves from cold air with textile cuffs. Children's membrane shoes usually use comfortable fasteners so that the baby can put on his own shoes, as well as a non-slip flexible sole for greater safety in icy conditions and reinforced heels and toes to maximize the life of the shoes.

Since membrane clothing and shoes were originally created for athletes and exhibit their properties optimally during active physical activity, children's membrane clothing is intended primarily for those who move a lot. This does not mean that you need to be in constant active movement to get the maximum effect from wearing membrane clothing, but for babies who mostly sit in a stroller during walks, such clothes or shoes are still not very suitable.

Membrane clothing is optimally suited for temperatures ranging from zero to minus 15-20 degrees. However, both outdoors and indoors, the child will feel comfortable and will not freeze or sweat.

3.How and with what to wear membrane shoes and clothes?

Manufacturers recommend wearing shoes or boots with a membrane on a sock or tights, which should not contain more than 10-20% cotton or wool, or on a thermal sock. This is due to the property of natural fabrics to absorb sweat and not release it, and membrane shoes are good because they allow the feet not to sweat, releasing steam molecules into the external environment. Therefore, it is better to give preference to hosiery with a predominance of artificial materials.

When it comes to membrane clothing, you should follow the three-layer rule: the first layer is thermal underwear, or underwear, which, as in the case of membrane shoes, should contain a minimum of natural materials. The second layer is light, for example, a fleece jacket or jacket. The third layer is the membrane jacket or overalls itself.

4.How to distinguish high-quality membrane clothing and shoes? What should you check when purchasing?

You will have to pay well for the comfort, lightness and convenience that membrane shoes and clothing are famous for. High-quality membrane children's clothes cannot be cheap, so the low price of membrane shoes or clothing should alert you. In this case, there is a possibility of buying something that will not last long and will not bring the expected result.

When buying membrane shoes for a child, you should pay attention to the quality of the sole. It should be flexible and elastic, then such shoes will last a long time. When choosing the appropriate size of shoes with a membrane, you need to take into account that the maximum effect from wearing it is achieved if there is free space inside the shoes. That is, the optimal shoe size will be a margin of 1 cm between the toe of the shoe and the tips of the toes.

When buying children's membrane clothing, pay attention to the quality of the seams. In high-quality clothing, the seams are additionally taped for a greater water-repellent effect.

5.How to care for membrane clothing and shoes?

Since things made using membrane technology are not cheap, it is necessary to take care of their preservation in their original form. Moreover, the properties of membrane clothing or shoes are fully manifested only when the integrity of the membrane is maintained and the wearing conditions are observed.

Prerequisites for preserving the protective properties of membrane shoes are cleanliness and dryness. Despite the fact that manufacturers additionally treat the top layer with protective agents, it is recommended to additionally impregnate membrane shoes with special compounds, especially in urban environments, where shoes are aggressively affected by water, dirt and salt.

After a walk, be sure to clean and wipe your shoes, and then dry them thoroughly. However, membrane shoes should not be dried near a radiator or heater, as this may destroy the membrane. The best option is to dry at room temperature, first tightly stuffing it with newspaper.

It is advisable to wash membrane clothing as rarely as possible so that water-repellent impregnations, in many cases DWR (Durable Water Repellence), applied to the top layer of clothing are not washed out. For minor stains, it is better to wait until the stain dries and brush off the dirt with a brush or wipe with a damp sponge without rubbing the dirt into the fabric. If you need to wash clothes frequently, it is better to take care of additional protection of the upper layers by using special compositions in the form of sprays after washing (for example, the English company NikWax is known for its line of water-repellent sprays for treating membrane clothing).

Membrane materials cannot withstand washing temperatures above 40 degrees, much less boiling. Aggressive chemicals (stain removers, solvents, washing powders with special additives) can have a destructive effect on the membrane and also break the tightness of taped seams of clothing.

Manufacturers do not recommend ironing membrane clothing. However, if necessary, you can use the lowest temperature and ensure minimal contact of the iron with the material so that the membrane does not have time to heat up.

6.What companies are represented in our country? Where can you buy membrane clothing and shoes in Belarus?

A wide range of children's clothing and shoes with membrane are presented in high-tech clothing and footwear stores from Finland for children and teenagers SuomiKids. The company is the official representative of Finnish manufacturers Reima and Kerry in Belarus.

The membrane is also available in the collections of the Czech brand Alpine Pro and the German company Jack Wolfskin. Companies offer winter and demi-season overalls, trousers and jackets.

In Belarus, membrane shoes can also be found in the collections of such footwear manufacturers for the whole family as Ecco (Gore-Tex® membrane is used), Alaska Original (own development - Antex & Alaskatex membrane), a large selection of children's membrane shoes is offered by the Kotofey trademark and “BARTEK”. To purchase membrane clothing or shoes in Belarus, we recommend that you familiarize yourself with the assortment in domestic online stores, where almost all of the listed brands are represented. There is also information in which stores or shopping centers you can try on and buy the model you like.

Summarizing…

...we note that high-quality membrane clothing and shoes are primarily suitable for active children; they are expensive and require special care, but at the same time they are comfortable, lightweight and excellent for walking in our climate with rapid changes in weather conditions.

Olga Bobko

Types of membrane

There are several types of membrane tissue: porous, non-porous, combined.

How do pore membranes work? Water falling on membrane clothing cannot penetrate it, since the pores of the fabric are too small. Accordingly, the fabric on the outside does not get wet. A fair question arises: “What to do with sweat secretions?” They are freely removed from the inside of the membrane tissue.

It is worth noting that such a membrane, like any breathing organism, “dies” relatively quickly. For example, when choosing the wrong washing mode, the pores of the membrane become clogged, which leads to a decrease in the breathability of clothes and loss of waterproofness.

In non-porous membranes, evaporation enters the inner part of the membrane and, through active diffusion, quickly passes to the outer side of the membrane clothing. Such membranes do not require special care, and they can please you for many years. However, it is worth saying that some lucky owners of such clothes, due to evaporation, sometimes have the feeling that the fabric still gets wet. But that's not true!

The most ideal is considered to be a fabric with a combined membrane, which is covered on the inside with a pore membrane. However, this magical clothing also has a significant drawback - its high price.

About the special relationship with membrane shoes...

It is worth emphasizing that you should not wait for perfectly dry shoes after jogging through puddles or snowdrifts. Since the membrane protects not the shoes, but the child’s feet from water. Water remains blocked inside the fabric, and the most reasonable solution in this case is, of course, proper drying.

It is important to know that steam removal will be faster in warm and dry weather than in wet and damp weather. Therefore, be prepared for the fact that on a very rainy autumn day after a walk, the child’s feet may not be dry enough - the difference between the internal microclimate and external conditions was not great enough and the rate of steam removal decreased. But if a child runs, the temperature and humidity inside the shoes increase and “push out” the moisture more and more. This suggests the conclusion that it is not recommended to buy such shoes for babies who still move little or sit in a stroller.

In order for the membrane to “breathe”, you need to monitor the condition of the shoes - the upper textile layer covered with dirt blocks evaporation. Special sprays will help in caring for such shoes, which will not only increase the water-repellent properties of the fabric, but also protect it from contamination.

What do the top experts say?

It would be a good idea to ask advice from mothers who already have such clothes or shoes in their child’s wardrobe. Where are you most likely to meet moms and dads on a sunny day? That's right, on the playground! Of the eleven mothers, two had experience of “communication” with such clothes, and one mother had experience with shoes.

Lena, mother of 4-year-old Lizochka:

“To be honest, when we bought a membrane jacket for the first time, we doubted its magical properties; it seemed a little thin to us then. We even played it safe and bought another down jacket, just in case. But they never put it on. The membrane was worn on a T-shirt at 0 degrees, and on a tank top at -20. It is important that dirt on such clothes can be removed with a regular napkin. This means that you can safely buy your favorite light shades and not worry that you will have to go to kindergarten to pick up your child with a spare jacket: it’s a shame to go home, much less go to a store or visit in grimy clothes.”

Ira, mother of Maxim and Vlad, 3 years old and 7 years old:

“The membrane overalls are just a godsend! Remember how our mothers and grandmothers wrapped us in brown fur coats, and tied a scarf on top. Here it was difficult to sit on the sled, let alone climb the hill. And it was not at all possible to undress myself. And the membrane overalls are light, comfortable, warm, beautiful. My son rides in it on the slide all the time. The child never sweated. It even seems to me that we began to get sick less, just like we bought our favorite light green overalls. In a word, I’m happy with the purchase!”

Marina, mother of 4-year-old Egor:

“We have sneakers with a membrane. We've been wearing it for the second season. The child likes it. I am pleased. Feet are always dry, regardless of the outside temperature. Unlike leather shoes, the child never complains about cold feet. I still haven’t lost my appearance, I think I’ll be able to carry my second child. Moreover, the color is quite universal. Yes, the price is more expensive than regular shoes, but it’s worth it.”

Olga Gael

Membrane (biology)

Image of a cell membrane. The small blue and white balls correspond to the hydrophilic heads of the lipids, and the lines attached to them correspond to the hydrophobic tails. The figure shows only integral membrane proteins (red globules and yellow helices). Yellow oval dots inside the membrane - cholesterol molecules Yellow-green chains of beads on the outside of the membrane - chains of oligosaccharides forming the glycocalyx

A biological membrane also includes various proteins: integral (penetrating the membrane through), semi-integral (immersed at one end in the outer or inner lipid layer), surface (located on the outer or adjacent to the inner sides of the membrane). Some proteins are the points of contact between the cell membrane and the cytoskeleton inside the cell, and the cell wall (if there is one) outside. Some of the integral proteins function as ion channels, various transporters and receptors.

Functions of biomembranes

• barrier - ensures regulated, selective, passive and active metabolism with the environment. For example, the peroxisome membrane protects the cytoplasm from peroxides that are dangerous to the cell. Selective permeability means that the permeability of a membrane to different atoms or molecules depends on their size, electrical charge and chemical properties. Selective permeability ensures that the cell and cellular compartments are separated from the environment and supplied with the necessary substances.

• transport - transport of substances into and out of the cell occurs through the membrane. Transport through membranes ensures: delivery of nutrients, removal of metabolic end products, secretion of various substances, creation of ion gradients, maintenance of the appropriate pH and ionic concentration in the cell, which are necessary for the functioning of cellular enzymes.

Particles that for some reason are not able to cross the phospholipid bilayer (for example, due to hydrophilic properties, since the membrane inside is hydrophobic and does not allow hydrophilic substances to pass through, or due to their large size), but necessary for the cell, can penetrate the membrane through special carrier proteins (transporters) and channel proteins or by endocytosis.

During passive transport, substances cross the lipid bilayer without energy consumption, by diffusion. A variant of this mechanism is facilitated diffusion, in which a specific molecule helps a substance pass through the membrane. This molecule may have a channel that allows only one type of substance to pass through.

Active transport requires energy as it occurs against a concentration gradient. There are special pump proteins on the membrane, including ATPase, which actively pumps potassium ions (K+) into the cell and pumps sodium ions (Na+) out of it.

• matrix - ensures a certain relative position and orientation of membrane proteins, their optimal interaction;

• mechanical - ensures the autonomy of the cell, its intracellular structures, as well as connection with other cells (in tissues). Cell walls play a major role in ensuring mechanical function, and in animals, the intercellular substance.

• energy - during photosynthesis in chloroplasts and cellular respiration in mitochondria, energy transfer systems operate in their membranes, in which proteins also participate;

• receptor - some proteins sitting in the membrane are receptors (molecules with the help of which the cell perceives certain signals).

For example, hormones circulating in the blood act only on target cells that have receptors corresponding to these hormones. Neurotransmitters (chemical substances that ensure the conduction of nerve impulses) also bind to special receptor proteins in target cells.

• enzymatic - membrane proteins are often enzymes. For example, the plasma membranes of intestinal epithelial cells contain digestive enzymes.

• implementation of generation and conduction of biopotentials.

With the help of the membrane, a constant concentration of ions is maintained in the cell: the concentration of the K+ ion inside the cell is much higher than outside, and the concentration of Na+ is much lower, which is very important, since this ensures the maintenance of the potential difference on the membrane and the generation of a nerve impulse.

• cell marking - there are antigens on the membrane that act as markers - “labels” that allow the cell to be identified. These are glycoproteins (that is, proteins with branched oligosaccharide side chains attached to them) that play the role of “antennas”. Because of the myriad configurations of side chains, it is possible to make a specific marker for each cell type. With the help of markers, cells can recognize other cells and act in concert with them, for example, in the formation of organs and tissues. This also allows the immune system to recognize foreign antigens.

Structure and composition of biomembranes

Membranes are composed of three classes of lipids: phospholipids, glycolipids and cholesterol. Phospholipids and glycolipids (lipids with carbohydrates attached) consist of two long hydrophobic hydrocarbon tails that are connected to a charged hydrophilic head. Cholesterol gives the membrane rigidity by occupying the free space between the hydrophobic tails of lipids and preventing them from bending. Therefore, membranes with a low cholesterol content are more flexible, and those with a high cholesterol content are more rigid and fragile. Cholesterol also serves as a “stopper” that prevents the movement of polar molecules from the cell and into the cell. An important part of the membrane consists of proteins that penetrate it and are responsible for the various properties of membranes. Their composition and orientation differ in different membranes.

Cell membranes are often asymmetrical, that is, the layers differ in lipid composition, the transition of an individual molecule from one layer to another (the so-called flip flop) is difficult.

Membrane organelles

These are closed single or interconnected sections of the cytoplasm, separated from the hyaloplasm by membranes. Single-membrane organelles include the endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, peroxisomes; to double membranes - nucleus, mitochondria, plastids. The outside of the cell is bounded by the so-called plasma membrane. The structure of the membranes of various organelles differs in the composition of lipids and membrane proteins.

Selective permeability

Cell membranes have selective permeability: glucose, amino acids, fatty acids, glycerol and ions slowly diffuse through them, and the membranes themselves, to a certain extent, actively regulate this process - some substances pass through, but others do not. There are four main mechanisms for the entry of substances into the cell or out of the cell: diffusion, osmosis, active transport and exo- or endocytosis. The first two processes are passive in nature, i.e. do not require energy consumption; The last two are active processes associated with energy consumption.

The selective permeability of the membrane during passive transport is due to special channels - integral proteins. They penetrate the membrane through, forming a kind of passage. The elements K, Na and Cl have their own channels. Relative to the concentration gradient, the molecules of these elements move in and out of the cell. When irritated, the sodium ion channels open and a sudden influx of sodium ions into the cell occurs. In this case, an imbalance of membrane potential occurs. After which the membrane potential is restored. Potassium channels are always open, allowing ions to slowly enter the cell