Issue 21/2022 - Porous thin-film solar engine successfully developed

Recently, Professor Liu Zunfeng and Professor Chen Yongsheng of the School of Chemistry of Nankai University and the team of Associate Professor Zhou Xiang of the School of Science of China Pharmaceutical University developed a self-oscillating artificial muscle driver based on porous flexible polypropylene/carbon black film, and explored the application as an engine to develop a "solar artificial muscle engine", opening up a new path
for the efficient use of solar energy.

According to reports, the study is the first to realize the self-oscillation drive under divergent light including sunlight, infrared light and simulated sunlight, and also realize the self-oscillation motion
under different scattered light irradiation angles.
This light-responsive self-oscillating driver has excellent oscillation work performance, excellent loading capacity and high energy conversion efficiency, and maintains a continuous oscillation motion without stopping
when the solvent is constantly supplied.

The researchers found that the introduction of a porous structure in the film can promote the mass transport of solvent molecules, resulting in faster bending speed and greater bending amplitude
of the film material.
Therefore, light-induced solvent evaporation based on porous membranes may be a good candidate to achieve self-oscillation drive
.

On this basis, the researchers finally designed and developed this self-oscillating driving film
based on sunlight.
It is mainly achieved by the reduction of alternating volumes on both sides of the polypropylene/carbon black polymer film caused by the evaporation of photothermal-derived solvents
.
Anisotropic solvent evaporation and rapid gradient diffusion in polymer films maintain oscillating bending drive
under the irradiation of divergent light.

Chen Yongsheng said that this work provides a new design strategy for "solar engines", which is conducive to the research and development of self-driving equipment, and will promote the interdisciplinary intersection of other fields, helping the rapid development of
smart devices such as smart materials and flexible devices.