Classification and Application of Waterproof and Breathable Fabrics
Waterproof and breathable fabrics refer to textiles that, during wear, prevent liquid water from penetrating under a certain pressure, while allowing perspiration from the human body to pass through in the form of water vapor, keeping the wearer dry and comfortable. The waterproof and breathable property is achieved based on the principle that water molecules are much larger than water vapor molecules. The pores on the surface of the fabric are much smaller than water droplets but significantly larger than water vapor molecules. Garments made from such fabrics can resist wind, rain, and snow while remaining breathable, preventing overheating during exercise and maintaining comfort when movement stops. If a fabric were only waterproof but not breathable, sweat would accumulate inside, making the wearer feel cold. Moreover, these fabrics are also wind-resistant, maintaining a layer of still air between the body and the garment for warmth. Without windproof performance, insulation would be ineffective, leading to a cold sensation.
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Types of Waterproof and Breathable Fabrics
Currently, there are three main types of waterproof and breathable fabrics:
High-Density Fabrics
These fabrics are made from high-count cotton yarns and superfine synthetic fibers woven into dense structures. They have high vapor permeability and moderate waterproof performance after water-repellent finishing. Their advantages include good breathability, softness, and drape, but they have low water resistance, a high defect rate, and difficulties in dyeing and finishing processes. Examples include superfine high-density fabrics and ultra-high-density cotton textiles.
Coated Fabrics
Coated fabrics are divided into hydrophilic and microporous types.
– Hydrophilic coatings form a continuous film on the fabric surface. Because the coating fills all pores, the fabric becomes waterproof. Hydrophilic polymer chains absorb moisture on the high-humidity side and release it on the low-humidity side through hydrogen bonding and molecular interaction.
– Microporous coatings contain fine pores that are small enough to block liquid water but large enough for water vapor molecules to pass through.
Although coated fabrics are easy to process, they have relatively low moisture permeability and hydrostatic pressure resistance.
Laminated Composite Fabrics
Laminated fabrics combine waterproofness, breathability, windproofness, and thermal insulation. They are made by laminating ordinary fabrics with expanded polytetrafluoroethylene (E-PTFE) membranes, complementing each material’s strengths. This technology represents the main development direction for waterproof and breathable materials today.
Currently, the latter two types—coated and laminated fabrics—are most widely used. Test data show that under normal temperature and static conditions, thermoplastic polyurethane (TPU) and PTFE offer comparable waterproof and breathable performance. However, under active or low-temperature conditions, TPU’s moisture transport capability decreases sharply due to molecular contraction, becoming almost zero below 0°C and brittle at -15°C. In contrast, E-PTFE maintains stable structure and moisture permeability from -150°C to -300°C.
Additionally, the micropores in E-PTFE form a complex network rather than straight channels, effectively blocking wind while allowing vapor transmission, thus providing both windproofing and thermal insulation. Therefore, E-PTFE is considered an ideal material for use in harsh environments.
Common Waterproof and Breathable Fabrics
Coated Fabrics
The earliest waterproof and breathable coated fabrics were made from materials such as polyvinyl chloride (PVC), polyethylene, neoprene rubber, and other synthetic rubbers. However, these materials had poor breathability, which often caused condensation inside garments and made wearers feel stuffy and uncomfortable.
Later, thermoplastic polyurethane (TPU) coatings were developed, offering excellent abrasion resistance, chemical and hydrolytic stability, low-temperature resistance, resistance to insects and mildew, easy coloration, and wide processing versatility. Both in terms of application and material performance, TPU coatings have seen significant advancement. Polyurethane coatings used for textile finishing vary in both raw materials and processing methods.
Microporous Coatings
Microporous coatings are formed by creating tiny pores within polyurethane during the film-forming process. These pores are small enough to block water droplets but large enough to allow water vapor molecules to pass through, thus achieving waterproof and breathable functionality. Typical products made using this method include ENTRANT (Toray, Japan), Ultrex (Burlington, USA), Porelle films (Stahi/ICI, Netherlands), and Ucecoat 2000(S) (UCB SpecialChemicals, Belgium).
Hydrophilic Non-Porous Polyurethane Coatings
Hydrophilic non-porous polyurethane coatings achieve breathability through hydrophilic groups or components that absorb, transfer, and desorb water molecules. Since there are no pores in the membrane, waterproof performance is excellent, although moisture permeability still needs improvement. These coatings typically require a water-repellent surface treatment to enhance waterproofing. Representative products include Witcoflex Staycool and X-liner (Baxenden Chemicals, UK), and Impraperm (Bayer, Germany).
Hybrid Hydrophilic–Microporous Coatings
These combine the features of both microporous and hydrophilic coatings. A hydrophilic non-porous layer is applied over a microporous film, or the microporous membrane is treated with hydrophilic agents to improve waterproofness without sacrificing vapor permeability. Examples include Thintech (3M, USA) and Entrant GII (Toray, Japan).
Shape-Memory Polyurethane Non-Porous Films
The principle behind shape-memory polyurethane films is that their moisture permeability changes with temperature—similar to human skin—achieving an intelligent moisture-regulating effect. As non-porous films, they provide excellent waterproof performance. Products such as Diaplex (Mitsubishi Heavy Industries, Japan) are suitable for both general and extreme environmental conditions, with waterproof, breathable, and thermal insulation properties that adapt to temperature changes, maintaining optimal comfort for the wearer.
Laminated Composite Fabrics
GORE-TEX Fabric
The breathability of GORE-TEX fabrics is achieved through an extremely thin membrane containing about 1.4 billion micro-pores per square centimeter. Each pore is approximately 20,000 times smaller than a water droplet and 700 times larger than a water vapor molecule, arranged irregularly. As a result, GORE-TEX fabrics can block rain, snow, and wind while allowing perspiration vapor to escape, forming a unique waterproof and windproof barrier. Standard GORE-TEX fabrics achieve waterproof ratings of 2000–3000 mm water column, while advanced versions from manufacturers in Taiwan and Korea reach 4000–6000 mm. However, moisture transmission requires that external humidity be lower than internal humidity; otherwise, vapor cannot escape and may even condense inside. A surface water-repellent treatment can improve water resistance but slightly reduce vapor permeability.
Sympatex Fabric
The key feature of Sympatex fabric is its use of a hydrophilic, non-porous polyester membrane that can be laminated onto various textiles or leather. Since it is non-porous, the membrane cannot be clogged by detergent residues or other particles, ensuring long-term breathability. Its waterproof and breathable mechanism relies on the different behaviors of liquid water and water vapor. In liquid form, water molecules cluster tightly together and cannot attach to the membrane’s polar molecular chains. In vapor form, the molecules move independently and are attracted to and transferred through the membrane by molecular polarity. This physical–chemical process allows vapor to escape from the inside while preventing liquid water from entering. Sympatex is renowned throughout Germany and Europe for its waterproof, windproof, and breathable performance.
DENTIK Fabric
DENTIK fabric, developed and produced by Denton Company (China), operates on the same principle as GORE-TEX, using a PTFE microporous membrane. The film features more than one billion pores per square centimeter and a porosity of up to 80%. The pore size is 700 times larger than vapor molecules—allowing sweat vapor to escape—but 10,000 times smaller than water droplets, preventing liquid penetration. As a result, DENTIK fabrics effectively allow natural perspiration while blocking wind, rain, and cold air, maintaining dryness and comfort even under severe weather conditions.
Applications of Waterproof and Breathable Fabrics
Military Applications
Waterproof and breathable fabrics were first developed and applied in the production of military uniforms and protective clothing. For air force pilots, naval sailors, and special operations soldiers, sudden immersion in cold water can cause rapid loss of body heat—one of the main factors leading to injury or death. Waterproof and breathable garments have therefore been adopted by the U.S. Air Force, naval crews, and special forces units engaged in sea, land, and air missions as special protective uniforms. These garments can provide up to two hours of protection in cold water at 7°C, while remaining lightweight and comfortable. The introduction of waterproof and breathable fabrics not only resolves the contradiction between ventilation and water resistance but also significantly reduces the weight of rain gear, thereby lightening soldiers’ overall load.
Civilian Applications
In civilian use, waterproof and breathable fabrics are most commonly applied in outdoor products such as tents, sleeping bags, jackets, and footwear. For instance, outdoor sleeping bags require warmth, breathability, and light weight. Fabrics laminated with PTFE microporous membranes are often used, featuring a double-layer structure: an outer nylon fabric and an inner PTFE membrane. Such sleeping bags pose no risk of hypoxia or carbon monoxide poisoning during use.
Because PTFE material has excellent chemical resistance and flame retardancy, along with its microporous film structure providing superior waterproof and breathable performance, it has become an ideal material for developing nuclear, biological, and chemical (NBC) protective clothing.
Waterproof and breathable laminated fabrics not only meet the clothing needs of people engaging in activities under harsh weather conditions such as extreme cold, rain, snow, and strong winds, but also cater to everyday needs such as raincoats and footwear. This gives the material broad prospects for application and development.
In the future, research and development on waterproof and breathable fabrics will focus on cost reduction, as well as achieving lighter weight, greater comfort, and multifunctionality.
Waterproof and breathable fabrics are high value-added products with wide-ranging applications. Different production techniques yield products with distinct characteristics, though each still has room for improvement. This calls for continued innovation and effort from researchers and engineers to develop fabrics with enhanced comfort and functionality, in order to meet the growing demands of modern consumers.
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