In recent work, researchers from the University of Louisville, US, have introduced a new class of functional materials based on carbon nanostructure thin-film polymer composites (TFPCs). Using polydimethylsiloxane, a common silicone elastomer, the team has fabricated composites with one-dimensional multi-wall carbon nanotubes (MWNTs), two dimensional single-layer graphene, two-and-a-half-dimensional graphene nanoplatelets and three dimensional highly ordered pyrolytic graphite. An evaporative mixing technique was utilized to achieve homogeneous dispersions of carbon in the polymer composites and their photomechanical responses to NIR illumination were studied.

For a given carbon concentration, both steady-state photomechanical stress response and energy-conversion efficiency were found to be directly related to the dimensional state of the carbon nanostructure additive. Actuation and relaxation kinetic responses were found to be related not to dimensionality, but to the percolation threshold of the carbon nanostructure additive in the polymer.

Wireless actuation

Studying the influence of the carbon nanostructure’s dimensional state on the mechanical response of the material could lead to new types of carbon-based mixed-dimensional composites for sensor and actuator systems. Furthermore, benefits of photomechanical actuation, such as wireless actuation, electromechanical decoupling (and therefore low noise) and massive parallel actuation of device arrays from a single light source, will provide researchers with an altogether different philosophy from which to pursue complex engineering challenges.

More information can be found in the journal Nanotechnology.