Enhancement and control of water vapor permeability and thermal conductivity of polymers: A review

Abstract

The water vapor permeability (WVP) and thermal conductivity of polymers are of great significance in personal cooling and even in responding to energy crises. This review attempts to discuss the factors that affecting these two properties at first, and then discusses the relationship between them from the aspects of hydrophilicity, porous structure, biomimetic layered structure, and so on. Generally, porous structure or hydrophilicity is beneficial to water vapor permeation, while dense structure is more conducive to the formation of heat conduction path and network, that is, to heat conduction. Of course, thermal conductive filler is the decisive factor for high thermal conductivity of polymer composites. Interestingly, the transmission process of water vapor also positively affects the heat conduction of polymer to a certain extent. Especially, the biomimetic fiber membrane with multi‐branch network following Murray's law, which integrates high WVP and high thermal conductivity, is one of the development directions of special concern. Finally, the related problems to be solved are put forward and prospected. It is hoped that this review will have positive guiding significance for developing polymer membranes and functional textile coatings with high moisture permeability and high thermal conductivity.

Influence of washability treatment on the electromagnetic interference shielding material’s comfort properties

“…Water vapor permeability refers to the fabric’s ability to adsorb and diffuse water vapor and is one of the indicators of the body’s ability to maintain the thermal balance between heat production and heat dissipation when the body loses heat and sweat. 44 In this paper, the water vapor permeability of fabric samples was characterized according to the ISO 11092 test standard, 45 and the test apparatus was Permetest (Sensora Instruments & Consulting, Czech Republic). The test sample size was 13 cm × 13 cm, and the test conditions should be set at approximately 20°C and 35% relative humidity.…”

Protocol to develop a moisture-desorptive passive cooling system for electronics thermal management

“…Some additives, including carbon nanotubes, graphene, and silica, can be added to porous membranes to enhance their thermal conductivities. 9 …”