Ultralight Nanofibrous Polyimide Aerogels with Outstanding Piezoelectric Performance for Acoustic Recognition

Abstract

Aerogels have emerged as ideal materials for extreme environments due to their excellent thermal insulation. However, conventional aerogels often suffer from poor mechanical properties, limited thermal stability, and inadequate breathability. Herein, a fluorinated polyimide (FPI) nanofibrous aerogel with ultralight weight, and high mechanical strength is constructed by moisture-assistant electrospinning for self-powered sensing. Due to the rapid phase transition of the charged jet through interaction between the fluorinated polyamic acid solution (FPAA) and water molecules, enabling the interweaving and cross-linking of nanofibers into a fluffy aerogel structure. Furthermore, the resulting FPI nanofibrous aerogels exhibit exceptional thermal insulation property with low thermal conductivity (0.045 W·m⁻¹·K⁻¹), super-hydrophobicity with water contact angle of 151° and superior moisture permeability of 10150 g/(m²·24 h). Moreover, the FPI nanofibrous aerogels show excellent piezoelectric properties (up to 34 V), rendering them ideal candidates for next-generation wearable electronics, particularly in high-precision physiological signal monitoring applications. In addition, the speech recognition system was able to recognize everyday sentences with precise detection of pauses and intonations. This work presents a novel strategy for designing FPI-based nanofibrous aerogels, paving the way for their practical applications in thermal insulation and self-powered sensing under extreme environmental conditions.

Graphical abstract

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