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Micrometer‐Scale Porous Buckling Shell Actuators Based on Liquid Crystal Networks
Author(s) -
Jampani Venkata Subba Rao,
Mulder Dirk J.,
Sousa Kevin Reguengo,
Gélébart AnneHélène,
Lagerwall Jan P. F.,
Schenning Albertus P. H. J.
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201801209
Subject(s) - microfluidics , materials science , micrometer , nanotechnology , actuator , porosity , buckling , capillary action , shell (structure) , fluidics , soft robotics , composite material , mechanical engineering , aerospace engineering , engineering , electrical engineering
Micrometer‐scale liquid crystal network (LCN) actuators have potential for application areas like biomedical systems, soft robotics, and microfluidics. To fully harness their power, a diversification in production methods is called for, targeting unconventional shapes and complex actuation modes. Crucial for controlling LCN actuation is the combination of macroscopic shape and molecular‐scale alignment in the ground state, the latter becoming particularly challenging when the desired shape is more complex than a flat sheet. Here, one‐step processing of an LCN precursor material in a glass capillary microfluidic set‐up to mold it into thin shells is used, which are stretched by osmosis to reach a diameter of a few hundred micrometers and thickness on the order of a micrometer, before they are UV crosslinked into an LCN. The shells exhibit radial alignment of the director field and the surface is porous, with pore size that is tunable via the osmosis time. The LCN shells actuate reversibly upon heating and cooling. The decrease in order parameter upon heating induces a reduction in thickness and expansion of surface area of the shells that triggers continuous buckling in multiple locations. Such buckling porous shells are interesting as soft cargo carriers with capacity for autonomous cargo release.