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Kinetics of Light-Responsive CNT / PNIPAM Hydrogel Microactuators.

Published version
Peer-reviewed

Repository DOI


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Authors

Gregg, Aoife 
De Volder, Michael 

Abstract

Light-responsive microactuators composed of vertically aligned carbon nanotube (CNT) forests mixed with poly(N-isopropylacrylamide) (PNIPAM) hydrogel composites are studied. The benefit of this composite is that CNTs act as a black absorber to efficiently capture radiative heating and trigger PNIPAM contraction. In addition, CNT forests can be patterned accurately using lithography to span structures ranging from a few micrometers to several millimeters in size, and these CNT-PNIPAM composites can achieve response times as fast as 15 ms. The kinetics of these microactuators are investigated through detailed analysis of high-speed videos. These are compared to a theoretical model for the deswelling dynamics, which combines thermal convection and polymer diffusion, and shows that polymer diffusion is the rate-limiting factor in this system. Applications of such CNT/hydrogel actuators as microswimmers are discussed, with light-actuating micro-jellyfish designs exemplified, and >1500 cycles demonstrated.

Description

Publication status: Published

Keywords

carbon nanotubes (CNTs), hydrogel, light actuation, microactuator, soft robotics, vertically aligned CNTs

Journal Title

Small

Conference Name

Journal ISSN

1613-6810
1613-6829

Volume Title

Publisher

Wiley
Sponsorship
European Commission Horizon 2020 (H2020) ERC (866005)
Engineering and Physical Sciences Research Council (EP/L027151/1)
Engineering and Physical Sciences Research Council (EP/L015978/1)
Engineering and Physical Sciences Research Council (EP/N016920/1)
Engineering and Physical Sciences Research Council (EP/P029426/1)
Engineering and Physical Sciences Research Council (EP/R020965/1)
Engineering and Physical Sciences Research Council (EP/S022953/1)
European Commission Horizon 2020 (H2020) Research Infrastructures (RI) (861950)
EPSRC (EP/V050923/1)
European Commission Horizon 2020 (H2020) ERC (883703)