Photopiezoelectric Composites of Azobenzene‐Functionalized Polyimides and Polyvinylidene Fluoride

Abstract

Light is a readily available and sustainable energy source. Transduction of light into mechanical work or electricity in functional materials, composites, or systems has other potential advantages derived from the ability to remotely, spatially, and temporally control triggering by light. Toward this end, this work examines photoinduced piezoelectric (photopiezoelectric) effects in laminate composites prepared from photoresponsive polymeric materials and the piezoelectric polymer polyvinylidene fluoride (PVDF). In the geometry studied here, photopiezoelectric conversion is shown to strongly depend on the photomechanical properties inherent to the azobenzene‐functionalized polyimides. Based on prior examinations of photomechanical effects in azobenzene‐functionalized polyimides, this investigation focuses on amorphous materials and systematically varies the concentration of azobenzene in the copolymers. The baseline photomechanical response of the set of polyimides is characterized in cantilever deflection experiments. To improve the photomechanical response of the materials and enhance the electrical conversion, the polyimides are drawn to increase the magnitude of the deflection as well as photogenerated stress. In laminate composites, the photomechanical response of the materials in sequenced light exposure is shown to transduce light energy into electrical energy. The frequency of the photopiezoelectric response of the composite can match the frequency of the sequenced light exposing the films.

Phototriggered Selective Actuation and Self‐Oscillating in Dual‐Phase Liquid Crystal Photonic Actuators

“…Further investigations aiming to reduce the energy dissipation should be carried out through direct integration of the photoactuator with piezoelectric material into a monolithic structure. To our best knowledge, this is the first report on the photoelectric energy conversion device from light energy to electric energy using a self‐oscillating polymer composite film, which is different from the previously reported photopiezoelectric composite film . This work provides new direction of the polymer actuators for applications in automated systems and energy ‐harvesting fields.…”

A Flexible Bilayer Actuator Based on Liquid Crystal Network and PVDF–TrFE for Low‐Grade Waste Heat Harvesting

“…[ 19–22 ] Combining light‐driven LCN films combined with piezoelectric materials, such as PVDF, can further convert mechanical motions to electrical energy. [ 23–26 ] Wei et al reported a near‐infrared (NIR) light‐triggered generator composed of a liquid crystal elastomer (LCE) and PVDF film. [ 26 ] Tang et al reported an optical pendulum generator that could generate electricity continuously by liquid crystalline actuators’ oscillation.…”

Smart Non-Woven Fiber Mats with Light-Induced Sensing Capability

“…Smart systems belong to the group of materials capable of changing the basic properties, when they are exposed to external stimuli such as electric [1][2][3], magnetic [4,5], thermal [6,7], pH [8,9], or light [10,11]. In case of light stimulation, such smart systems can exhibit the shape [12] or resistivity [13] change or generate electric output [14].…”