Mechanically flexible, waterproof, breathable cellulose/polypyrrole/polyurethane composite aerogels as wearable heaters for personal thermal management

Abstract

Multifunctional wearable heaters are highly desirable for the growing demand in the field of personal thermal management. Herein, we present an efficient and feasible strategy to construct wearable heaters using waterproof and breathable composite aerogels made from cellulose nanofibers (CNF) aerogel, polypyrrole (PPy), fluorinated finishing agent and polyurethane (PU). The named composite aerogels exhibited a lightweight structure (0.14 g/cm3), superior mechanical robustness and outstanding Joule heating performance (up to 173 °C at 4 V about 70 s). They feature a water contact angle (WCA) up to 135° enabled by the synergistic effect of the fluorinated agents and surface roughness. The aerogels also exhibited high air permeability (186.6 ± 22 L S−1 m−2) and satisfiable water vapor transmission (WVT) rate at 5.8 ± 0.8 kg m−2 d−1. These favorable features made the composite aerogels highly promising for intelligent garments, wearable devices and personal thermal management systems.