Phase Change materials in Active Sportswear: Concept, Current Research Finding, Challenges and Opportunities Shamini Rajaganesh
University of Texas at Austin
This paper extensively explores the new technology of Phase Change Materials in textiles and Clothing. Phase Change Materials are capable of absorbing, storing and releasing heat under certain temperature ranges over which they change from one phase to the other. The heat is stored in the form of latent heat. This unique property of PCMs can be used to produce fabrics and other textile materials with thermal acclimatizing property. The working of PCMs in textiles, manufacturing and incorporation methods are discussed in great detail. Moreover, the area of PCM application in the field of active sportswear is discussed in relation to the thermo-physiological comfort. The challenges and opportunities in this innovative area are identified and listed.
Phase Change materials in Active Sportswear: Concept, Current Research Finding, Challenges and Opportunities
Man, as one of the highly evolved living being on Earth, has never been satisfied with his own inventions. He strives to invent a new product and keeps striving to make that one product better. Right from its inception, a telephone has undergone countless modifications to become the smart phone that it is today. Similarly, one of the oldest inventions of the human race is textiles and clothing. What was created as a tool for protection from the harsh environment has taken different faces over the course of human evolution. Today, the timeline of this field shows innumerous innovations. As man is progressing, he wants his basic necessities to also evolve and suit his lifestyle. Even textiles and clothing, one of the most basic and primary needs of man, has evolved to take up the tag of being ‘smart’. Smart textile materials can be defined as the materials and structures that sense and react to environmental conditions or stimuli, such as those from mechanical, thermal, chemical, electrical, magnetic or other sources. (Tao, 2001) According to the manner of reaction, they can be divided into passive smart, active smart and very smart textiles. Passive smart materials can only sense the environmental conditions or stimuli; active smart materials can sense, react to the conditions or stimuli; very smart materials can sense, react and adapt themselves accordingly. Fibre and textile which have automatic acclimatizing properties have been recently attracting more and more attention. This effect can be achieved by using Phase Change Materials (Mondal, 2007). Phase Change Materials, otherwise known as PCM, falls into the category of active smart textiles. They were originally developed by a NASA research program to be used in space suits. A phase change is the process of changing from one physical state to another. PCM can be defined as ‘those materials that can absorb, store and release large amounts of energy, in the form of latent heat, over a narrowly defined phase change range, during which the material changes state’ (Bendknowska and Wrzosek, 2009). Each PCM has a specific phase change range, defined in terms of its melting temperature and crystallization temperature. During melting, the solid PCM absorbs heat from the environment as latent heat. This heat energy is used to break down the chemical bonds that are responsible for the solid structure. This energy is stored in the liquid state PCM. When the PCM reaches its crystallization temperature, it begins the cooling process. The heat energy stored in the PCM is now released. The schematic representation of the phase change process is shown in Figure 1. During this entire phase change process, the temperature of the PCM as well as the surrounding substrate remains constant (Bendknowska and Wrzosek, 2009). Because of this property, the use of PCMs has extended from their original space suit application and is now widely explored for...