Reversible Hydration Composite Films for Evaporative Perspiration Control and Heat Stress Management

Abstract Donning of personal protective equipment (PPE) in the healthcare sector has been intensified by the on‐going COVID‐19 pandemic around the globe. While extensive PPE provides protection, it typically limits moisture permeability and severely hinders the sweat evaporation process, resulting in greater heat stress on the personnel. Herein, a zinc‐poly(vinyl alcohol) (Zn‐PVA) composite film is fabricated by embedding a super‐hygroscopic zinc‐ethanolamine complex (Zn‐complex) in the PVA matrix. By attaching the Zn‐PVA composite film, the relative humidity (RH) inside the protective suit decreases from 91.0% to 48.2%. The reduced RH level, in turn, enhances evaporative cooling, hence bringing down the heat index from 64.6 to 40.0 °C at an air temperature of 35 °C, remarkably lowering the likelihood of heat stroke. The American Society for Testing and Materials tests conducted on a sweating manikin have also proven that the Zn‐PVA composite films can significantly reduce the evaporative resistance of the protective suit by 90%. The low material cost, facile fabrication process, and reusability allow the Zn‐PVA composition films to be readily available for healthcare workers worldwide. This application can be further extended to other occupations that are facing severe thermal discomfort and heat stress.