posted on 2023-06-09, 18:17authored byConor Boland, Umar Khan, Gavin Ryan, Sebastian Barwich, Romina Charifou, Andrew Harvey, Claudia Backes, Zheling Li, Mauro S Ferreira, Matthia E Möbius, Robert J Young, Jonathan N Coleman
Despite its widespread use in nanocomposites, the effect of embedding graphene in highly viscoelastic polymer matrices is not well-understood. We add graphene to a lightly cross-linked polysilicone, often encountered as Silly Putty, changing its electro-mechanical properties significantly. The resulting nanocomposites display unusual electromechanical behavior such as post-deformation temporal relaxation of electrical resistance and non-monotonic changes in resistivity with strain. These phenomena are associated with the mobility of the nanosheets in the low-viscosity polymer matrix. By considering both the connectivity and mobility of the nanosheets, we develop a quantitative model that completely describes the electromechanical properties. These nanocomposites are sensitive electromechanical sensors with gauge factors >500 which can measure pulse, blood pressure and even the impact associated with the footsteps of a small spider.
History
Publication status
Published
File Version
Accepted version
Journal
Science
ISSN
0036-8075
Publisher
American Association for the Advancement of Science