Work

Humidity-sensing and light-controlled steering azobenzene liquid crystal elastomer actuators

Year: 2026

Type: article

Abstract: A main-chain liquid crystal elastomer (LCE) with amino-azobenzene mesogens was synthesized via thiol-acrylate Michael addition reaction and used to make rod actuators with aligned mesogens. The use of amino-azobenzene mesogens endows the LCE actuator with dual capabilities of colorimetric humidity sensing and light-controlled rolling motion on a hot substrate surface. On the one hand, a simple acid treatment results in protonation of surface amino-azobenzene moieties, enabling the LCE to change color reversibly depending on the relative humidity of its environment, with high humidity leading to deprotonation and low humidity prone for protonation. On the other hand, for LCE rod actuator rolling on a hot surface, localized light irradiation perturbs this self-sustained motion through photoisomerization and photothermal effects, achieving light-controlled braking, reversal, and steering. The irradiation intensity and position precisely modulate the parking time (duration of still state) and the curvature change, allowing navigable and obstacle-avoiding locomotion. This study demonstrates an integrated strategy to couple thermal and optical stimuli within a fully azobenzene-based LCE system, opening new opportunities for adaptive soft actuators and robots.

Source: Chemical Engineering Journal

DOI: 10.1016/j.cej.2026.178901

Authors: Long Xu, Shaoxia Zhang, Zeping Liu, Yue Zhao

Institution: Université de Sherbrooke

Language: English

Topic: Advanced Materials and Mechanics

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,830

Funders: Centre québécois sur les matériaux fonctionnels, China Scholarship Council, Natural Sciences and Engineering Research Council of Canada, Fonds de recherche du Québec – Nature et technologies