Photopolymerization-Driven Macroscopic Mechanical Motions of a Composite Film Containing a Vinyl Coordination Polymer

We report a unique vinyl coordination polymer (CP), [Zn(4-Fb)(2)(tkpvb)](n) (1, 4-HFb=4-fluorobenzoic acid, tkpvb=1,2,4,5-tetrakis(4-pyridylvinyl)benzene) that undergoes a rare photopolymerization reaction to form a two-dimensional CP integrated with a one-dimensional linear organic polymer. Upon light irradiation at different wavelengths, 1 exhibits an unprecedented phenomenon of photoinduced nonlinear lattice expansion. 1 can be uniformly dispersed in polyvinyl alcohol (PVA) to form the composite film of 1-PVA. When this film is exposed to UV light, internal minute stresses within crystallites are released by lattice expansion, resulting in a variety of photopolymerization-driven macroscopic mechanical motions. The findings provide new insights into the conversion of small lattice expansions of CPs into macroscopic mechanical motions based on photopolymerization reactions, which can promote the development of CPs-based smart photoactuators in the burgeoning field of microrobotics.

Automated summary

We have reported a unique vinyl coordination polymer (CP), [Zn(4-Fb)(2)(tkpvb)](n), which can undergo a rare photopolymerization reaction to form a two-dimensional CP integrated with a one-dimensional linear organic polymer. This CP exhibits a phenomenon of photoinduced nonlinear lattice expansion upon light irradiation at different wavelengths. It can be dispersed in polyvinyl alcohol (PVA) to form a composite film, which can undergo various photopolymerization-driven macroscopic mechanical motions when exposed to UV light. These findings provide new insights into the development of CPs-based smart photoactuators, which can be applied in the field of microrobotics.