Available on the membrane of shoes, choose shoes for the winter If 10 years ago about buying clothes membrane thought only advanced athletes and skiers, but now it becomes a part of life not only of many adults walking to work, but also children, and practically from birth. What is membrane? Let's start with definitions: Membrane (from lat.membrna "parchment") – a film, usually serving as a semipermeable separator media (including the shell) or oscillating surface. . "Membrane – it's either very fine film that is laminated (welded or glued to the special technology) to the upper fabric, or special treatment, firmly stamped on fabric with hot way during manufacture. From inside the film or impregnation may be protected by another layer of fabric.
" What is the principle of the membranes? They have a structure in the form of a film with a pore size of several thousand times smaller water droplets, but most of the H2O molecule, so the drop just does not pass through them. This ensures water resistance. But the water vapor molecules pass through the pores freely. When you sweat, there difference in partial pressure of water vapor inside the shoe and out. This is the driving force for removal of vapor that is expelled. Why the child is cold? Most likely so: 1. Too tight shoes – immobilized fingers are freezing.
Too big – no heat-effect. 2. Hundred with legs (extra toes). Leg alternately sweats and cools. 3. or socks without synthetic membrane under boots.