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 crosslinked 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 nonmonotonic 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.
The synthesis of five new 2,6-bis(1,2,3-triazol-4-yl)pyridine (btp) ligands is described: the self-assembly behaviour of the tri-methyl ester, 1, with Eu(III) showed the formation of a luminescent 1:3 Eu : btp complex, Eu13, which was studied in solution and in the solid state; while the tri-carboxylic acid, 2, formed a hydrogel and its corresponding complex Eu23, gave rise to a strongly red luminescent healable metallogel.
The preparation of functional supramolecular constructs is an area of significant interest in the materials science community, and as the field continues to mature, a prevalent focus for such materials is now the incorporation of stimuli-responsive properties for specific applications.
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