A steric hindrance-directed grafting strategy for precise functionalization of cellulose enabling high-performance triboelectric textiles
Tianmei Lyu, Chuanhui Wei, Jin He, Yuxin Ma, Yi Luo, Xiaoxuan Fan, Yiwei Ouyang, Xiao Peng, Kai Dong
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.