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Biomimetic Reversible Heat-Stiffening Polymer Nanocomposites.

Authors :
Cudjoe E
Khani S
Way AE
Hore MJA
Maia J
Rowan SJ
Source :
ACS central science [ACS Cent Sci] 2017 Aug 23; Vol. 3 (8), pp. 886-894. Date of Electronic Publication: 2017 Jul 26.
Publication Year :
2017

Abstract

Inspired by the ability of the sea cucumber to (reversibly) increase the stiffness of its dermis upon exposure to a stimulus, we herein report a stimuli-responsive nanocomposite that can reversibly increase its stiffness upon exposure to warm water. Nanocomposites composed of cellulose nanocrystals (CNCs) that are grafted with a lower critical solution temperature (LCST) polymer embedded within a poly(vinyl acetate) (PVAc) matrix show a dramatic increase in modulus, for example, from 1 to 350 MPa upon exposure to warm water, the hypothesis being that grafting the polymers from the CNCs disrupts the interactions between the nanofibers and minimizes the mechanical reinforcement of the film. However, exposure to water above the LCST leads to the collapse of the polymer chains and subsequent stiffening of the nanocomposite as a result of the enhanced CNC interactions. Backing up this hypothesis are energy conserving dissipative particle dynamics (EDPD) simulations which show that the attractive interactions between CNCs are switched on upon the temperature-induced collapse of the grafted polymer chains, resulting in the formation of a percolating reinforcing network.

Details

Language :
English
ISSN :
2374-7943
Volume :
3
Issue :
8
Database :
MEDLINE
Journal :
ACS central science
Publication Type :
Academic Journal
Accession number :
28852703
Full Text :
https://doi.org/10.1021/acscentsci.7b00215