2010-Sweat Rate of Thermostatic Smart Clothing using Nanoencapsulated Phase Change Materials

Sweat Rate of Thermostatic Smart Clothing using Nanoencapsulated Phase Change Materials

Kyeyoun Choi, Oklahoma State University


Introduction

Clothing comfort depends on many factors such as the temperature of the environment, the relative humidity, the wind velocity, the metabolism of the wearer and, of course, the characteristics of the clothing materials. And many other factors such as colour, fashion, a person’s physical and psychological state also influence the comfort.
The requirements of clothing material are satisfied by not only mechanical and dimensional properties but also thermal comfort properties. Phase change materials (PCMs) are able to change their phases with absorbing, storing, and releasing latent heat according to the heat flux between the PCMs and ambient environment or PCMs and human body dynamically and reversibly. The paraffin hydrocarbon (Alkanes, CnH2n+2) are mainly used PCMs because they have wide range of melting temperature depending on the number of carbon, non-toxic and inexpensive.
The PCMs in clothing are looked forward to playing roles in balancing temperature, reducing overheating, minimizing sweating, reducing chilling, and regulating temperature actively. Therefore, the materials can be used as an effective material in regulating body temperature and thermal comfort.
The perspiration occurs along with a body movement or exercise because it is physiological response for maintaining homeostasis of body through regulating the body temperature. If sensible perspiration which is generally called sweating is started after insensible perspiration, it has to be controlled rapidly because of physiological loss or discomfort of a body.
Furthermore, the body temperature is dropped easily because moisture is evaporated with heat from the body when a human exercises in cold environment. Therefore, to lead thermal regulating before over sweating by thermostatic clothing is desirable and it plays not only an important role in thermal comfort as maintaining body homeostasis, but can be also used as an index measuring the level of a person’s thermal regulation. The perspiration rate is influenced by diverse factors like intensity of exercise, physical strength, ambient condition and clothing materials.
In this study, the sweat rates of thermostatic sportswear treated with vapor permeable water repellency (VPWR) and nanoencapsulated PCMs (nanoPCMs) for active discharge of moisture from perspiration were examined for confirmation of the effectiveness as a thermostatic smart clothing material.