Fast, light-responsive, metal-like polymer actuators generating high stresses at low strain

Verpaalen, Rob C.P.; Varghese, Shaji; Froyen, Arne; Pilz da Cunha, Marina; Pouderoijen, Maarten J.; Severn, John R.; Bhatti, Muhammad R.; Peijs, Ton; Bastiaansen, Cees W.M.; Debije, Michael G.; Engels, Tom A.P.; Schenning, Albertus P.H.J.

Abstract

Producing lightweight polymeric actuators able to generate high stresses typical of hard metals and/or ceramics remains challenging. The photo-mechanical responses of ultra-drawn ultra-high molecular weight polyethylene (UHMWPE) actuators containing azobenzene photo-switches with symmetrically attached polyethylene (PE) side chains are reported. Long PE side chains promote dispersion within the apolar UHMWPE matrix, and the ultra-drawn films are highly aligned. The ultra-drawn azobenzene-doped UHMWPE films have high Young's moduli (∼100 GPa) and are viscoelastic at room temperature at strains below 1%. The photo-mechanical response of the films is fast (<1 s), showing a high specific actuation stress response (>6 × 104 Pa (kg m−3)−1) to UV or visible light at a low strain (∼0.06%). The actuator responds to rotating linearly polarized light, causing a photo-induced stress wave response. Such rapid, high-stress, low-strain, photo-mechanical responses are unique in soft polymer systems with physical values approaching hard metals/ceramics.

• Journal Article Type: Article
• Acceptance Date: Mar 2, 2020
• Online Publication Date: Mar 30, 2020
• Publication Date: Jun 3, 2020
• Deposit Date: Sep 7, 2023
• Journal: Matter
• Electronic ISSN: 2590-2385
• Publisher: Cell Press
• Peer Reviewed: Peer Reviewed
• Volume: 2
• Issue: 6
• Pages: 1522-1534
• DOI: https://doi.org/10.1016/j.matt.2020.03.001
• Public URL: https://uwe-repository.worktribe.com/output/11076812