A steric hindrance-directed grafting strategy for precise functionalization of cellulose enabling high-performance triboelectric textiles

Abstract

As an abundant and biocompatible biopolymer, cellulose exhibits great potential in sustainable triboelectric energy harvesting. However, its inherently weak molecular polarity severely limits mechano-electric conversion performance. Herein, we develop a precision molecular polarity engineering strategy that significantly enhances interfacial charge transfer by grafting strongly electron-donating and electron-withdrawing groups onto cellulose macromolecular chains, respectively. This strategy involves a two-step grafting reaction process controlled by steric hindrance effect. Initially, small-molecule intermediates with low steric hindrance are selectively installed onto the highly active C6 hydroxyl groups via a “grafting to” method, establishing well-defined controlled polymerization sites. Subsequently, high-polarity amino/fluoro-containing moieties are precisely introduced through a “grafting from” polymerization, with the grafting degree finely regulated by initiator concentration modulation. Through combined experimental and computational studies, a quantitative structure-property relationship is established, revealing that molecular polarity enhancement can effectively improve interfacial charge transfer efficiency. As a result, the optimized cellulosic triboelectric textile demonstrates a remarkable enhanced charge density of 48.5 μC m⁻² with more than four-fold improvement, enabling its successful applications in emergency power systems and self-powered sensors. This work provides a transformative precision molecular polarity engineering strategy for designing next-generation high-performance triboelectric biopolymers.