posted on 2024-03-04, 15:30authored byDawei Wang, Chen Xin, Liang Yang, Liu Wang, Bingrui Liu, Hao Wu, Chaowei Wang, Deng Pan, Zhongguo Ren, Yanlei Hu, Jiawen Li, Jiaru Chu, Dong Wu
Inspired by the reverse thrust generated by fuel injection,
micromachines
that are self-propelled by bubble ejection are developed, such as
microrods, microtubes, and microspheres. However, controlling bubble
ejection sites to build micromachines with programmable actuation
and further enabling mechanical transmission remain challenging. Here,
bubble-propelled mechanical microsystems are constructed by proposing
a multimaterial femtosecond laser processing method, consisting of
direct laser writing and selective laser metal reduction. The polymer
frame of the microsystems is first printed, followed by the deposition
of catalytic platinum into the desired local site of the microsystems
by laser reduction. With this method, a variety of designable microrotors
with selective bubble ejection sites are realized, which enable excellent
mechanical transmission systems composed of single and multiple mechanical
components, including a coupler, a crank slider, and a crank rocker
system. We believe the presented bubble-propelled mechanical microsystems
could be extended to applications in microrobotics, microfluidics,
and microsensors.