Emerging Materials and Strategies for Personal Thermal Management

Abstract

us warm in cold climates and shielded us from the nakedness for modesty and civilization. [1,2] Cloth is also a platform for artists, designers, and tailors to advance the clothing demands with emerging materials, process, and fashion. [2] While the majority of the functionalities of clothes lie in their physical attributes, such as their softness, breathability, air/ vapor permeability, and, of course the appearance, their role in thermal management is equally, if not more, important. The primary goal of clothing is to satisfy human being's basic needs in thermal comfort, by providing cooling in the hot environment or heating in the cold environment. [1] The energy management aspect of clothing is becoming an increasingly important and attractive aspect due to our increasing awareness to energy consumption and our persisting pursuit of comfort and health. The finite availability and the associated environmental consequence of fossil fuels have motivated us to save energy from virtually all aspects of our daily lives. A suitable thermal envelop is a necessity for our living and working. To create a comfortable indoor environment, the building heating, ventilation, and air conditioning (HVAC) systems are widely used for space cooling and heating at the expense of excessive energy consumption. [3][4][5][6] According to United States In this decade, the demands of energy saving and diverse personal thermoregulation requirements along with the emergence of wearable electronics and smart textiles give rise to the resurgence of personal thermal management (PTM) technologies. PTM, including personal cooling, heating, insulation, and thermoregulation, are far more flexible and extensive than the traditional air/liquid cooling garments for the human body. Concomitantly, many new advanced materials and strategies have emerged in this decade, promoting the thermoregulation performance and the wearing comfort of PTM simultaneously. In this review, an overview is presented of the state-ofthe-art and the prospects in this burgeoning field. The emerging materials and strategies of PTM are introduced, and classed by their thermal functions. The concept of infrared-transparent visible-opaque fabric (ITVOF) is first highlighted, as it triggers the work on advanced PTM by combining it with radiative cooling, and the corresponding implementations and realizations are subsequently introduced, followed by wearable heaters, flexible thermoelectric devices, and sweat-management Janus textiles. Finally, critical considerations on the challenges and opportunities of PTM are presented and future directions are identified, including thermally conductive polymers and fibers, physiological/psychological statistical analysis, and smart PTM strategies.

Conformable on-skin devices for thermo-electro-tactile stimulation: materials, design, and fabrication

“…Such devices can adhere perfectly to the skin thanks to Van der Waals forces, therefore making them an attractive platform for other skin electronics applications. 125 In any case, despite the known Joule heating properties of PEDOT:PSS, 96,124,126 and its use as a coating for fabrics to be used a heating clothing (we will not address these devices here as Lu et al covered them in detail in a recent review, 68 ), one can only find limited examples of CP-based conformable heaters in the literature. Zhou et al developed a conductive composite of PEDOT:PSS and waterborne PU with remarkable stretchability; the addition of in situ generated rGO (GO reduction with HI), while improving only slightly the conductivity, increased dramatically the thermal conductivity of the films.…”

“…[65][66][67] In recent years heaters have attracted increasing attention also in the medical field: the use of new materials and new fabrication techniques allowed the development of numerous conformable and stretchable heaters to directly mount on human skin. Thermal stimulation is important in personal thermal management (PTM) technologies 68 where one of the most important applications in this sense is in physical treatments and, in particular, in thermotherapy. The latter can be defined as the therapeutic application of heat to specific regions of the body resulting in an increased temperature in the tissue, 69 often useful for the treatment of musculoskeletal disorders.…”

A review of thermal interface material fabrication method toward enhancing heat dissipation

“…Therefore, the area will give lower thermal conductivity due to the resistance for heat flow in the void spaces 41 . Many researchers nowadays focused on the enhancement materials properties, surface contact, and materials bond formation to have good thermal performance and heat dissipation 3,42‐44 . Thermal resistance measurement usually conducted using the laser flash method, simulation studies, temperature measurement, and others 45‐47 .…”

“…41 Many researchers nowadays focused on the enhancement materials properties, surface contact, and materials bond formation to have good thermal performance and heat dissipation. 3,[42][43][44] Thermal resistance measurement usually conducted using the laser flash method, simulation studies, temperature measurement, and others. [45][46][47] Most of the conventional TIMs that are available in the market are conductive thermal greases, solder, and PCMs, while…”

Metamaterials-Enabled Sensing for Human-Machine Interfacing

“…Thermal/infrared sensing is more promising in HMI applications since it can be used to sense objects and environments through the infrared light as all objects emit infrared light at anytime and anywhere [ 14 , 15 , 16 , 85 , 86 , 87 , 88 , 89 , 90 ]. Lochbaum et al combined microelectromechanical system (MEMS) and metamaterial perfect emitter to achieve narrowband on-chip infrared emitter for infrared sensing [ 91 ].…”