[nanoPost] Breathable Polyurethanes for Sportswear, Workwear and Medical Textiles

Company UK 

Types of Waterproof, Breathable Membranes

Hydrophilic Polyurethanes
 - As membranes (coatings and films)
  - Main textile-related applications
 - Unusual (“intelligent”) characteristics
 - Breathability of clothing layers
 - Water vapour resistance spectrum 
 - Nanostructure (highly simplified)
 - How they work (interaction with water   at the molecular level)

Hydrophilic polyurethanes are strange beasts.  They flout the basic laws of physics, they have an inverse temperature dependency and they show “intelligent” behaviour in responding to a stimulus.  In the latter instance, they react like human skin and biological polymers such as keratin.  Some types exhibit characteristics of phase change materials (PCMs) and shape memory polymers (SMPs) at normal ambient temperatures. 

In simple terms, we are describing copolymers with alternating hydrophilic and hydrophobic nano-segments in their backbones.  By carefully controlling the size, shape and relative proportions of these segments, we can vary the breathability and physical properties of the polymer to satisfy a spectrum of requirements.  Thus, we can make a range of polymers that is suited for occlusive wound dressings, waterproof-yet-breathable fabrics for foul-weather clothing and various hygienic textile coatings.