Biomimetic thermoresponsive superstructures by colloidal soft-and-hard co-assembly

Abstract

Soft-and-hard hybrid structures are ubiquitous in biological systems and have inspired the design of man-made mechanical devices, actuators, and robots. The realization of these structures, however, has been challenging at microscale, where material integration and actuation become exceedingly less practical. Here, through simple colloidal assembly, we create microscale superstructures consisting of soft and hard materials, which, serving as microactuators, have thermoresponsive shape-transforming properties. In this case, anisotropic metal-organic framework (MOF) particles as the hard components are integrated with liquid droplets, forming spine-mimicking colloidal chains via valence-limited assembly. The chains, with alternating soft and hard segments, are referred to as MicroSpine and can reversibly change shape, switching between straight and curved states through a thermoresponsive swelling/deswelling mechanism. By solidification of the liquid parts within a chain with prescribed patterns, we design various chain morphologies, such as “colloidal arms,” with controlled actuating behaviors. The chains are further used to build colloidal capsules, which encapsulate and release guests by the temperature-programmed actuation.

Electrochemically-driven actuators: from materials to mechanisms and from performance to applications

“…123 For instance, a combination of soft and rigid materials can yield actuator systems with both fine manipulation and robust locomotion capabilities. 399,400 This hybrid approach not only broadens the operational scope of actuators but also brings us closer to mimicking the complex and adaptive movements found in natural biological systems.…”

Magnetically locked Janus particle clusters with orientation-dependent motion in AC electric fields

“…Micromotors composed of active colloidal particles have found use in a multitude of applications, including drug delivery, 1–4 cell manipulation, 5–7 flexible electronics, 8–10 and cargo transport. 11–15 Such micromotors can be propelled by various energy sources, including magnetic, 16–21 acoustic, 2,22–24 and electric fields, 11,25–28 as well as catalytic reactions. 29–33 As a category of electrical stimulation, induced-charge electrophoresis (ICEP) is a useful method to drive the motion of metallodielectric particles ( e.g.…”

“…Micromotors composed of active colloidal particles have found use in a multitude of applications, including drug delivery, [1][2][3][4] cell manipulation, [5][6][7] flexible electronics, [8][9][10] and cargo transport. [11][12][13][14][15] Such micromotors can be propelled by various energy sources, including magnetic, [16][17][18][19][20][21] acoustic, 2,[22][23][24] and electric fields, 11,[25][26][27][28] as well as catalytic reactions. [29][30][31][32][33] As a category of electrical stimulation, induced-charge electrophoresis (ICEP) is a useful method to drive the motion of metallodielectric particles (e.g., dielectric particles with metal patches) in alternating current (AC) electric fields due to the highly tunable interactions between the particles and applied field.…”