We often assume that garments containing microporous membranes, which are both "waterproof" and "breathable", would perform equally good in all circumstances. However, tests at Sports Tech Research Centre show that outer air temperature, humidity and even what we wear under such clothes affect how well they work.
Studies of the moisture transport through fabrics and garments containing microporous membranes in realistic conditions illustrate the importance of recognizing the key properties of such materials. Moisture transport by microporous membranes is governed by diffusion, and strongly depends on the temperature and humidity of the air on both sides of the membrane.
- This means that garments and footwear containing such membranes will potentially behave quite differently when ambient air humidity dramatically changes, and even when we change what we put under them. The garments can be very effective for ambient conditions with low humidity and low temperatures, and much less effective in moisture transport from the body in rainy conditions or warm, wet weather, says Mikael Bäckström, head of Sports Tech Research Centre.
The researchers at the Sports Tech Research Centre use a tailor-made sensor system that combines temperature and humidity sensors to assess the performance and comfort of the garments. These tests are conducted under realistic conditions in the wind tunnel at the Sports Tech Research Centre, on a running treadmill, with a control over ambient air temperature and humidity.
Realizing that standard tests of the microporous membranes does not fully reflect how fabrics containing them will perform at different conditions, new laboratory setup is made for in-depth studies. The aim of the research is developing new methods that allow testing different membrane-containing materials in environments that correspond to the conditions in which they will be used, giving manufacturers more reliable information for their product development.