Abstract

Designing artificial micro-components is key to developing new functionality at small scales that can mimic, and perhaps match or surpass, biological counterparts. I will talk about two recent theoretical developments I have worked on in this area: artificial swimming and shape-change actuation. Firstly, I will present the development of a slender body theory for chemically-active microswimmers, which self-propel by consuming solute fuel. This theory significantly simplifies the calculation of the swimming behaviour of slender filaments with arbitrary 3D centreline, thickness variations and chemical patterning. I shall explore some interesting examples, such as looped and knotted structures. The second part of the talk will discuss how shape-shifting actuators can be designed from the controllable swelling and shrinking of responsive hydrogels. These poroelastic materials absorb or expel water, depending on an external stimulus. We shall consider the dynamics of this size-change behaviour, and how it can be exploited to make microcomponents from a single material that exhibit anisotropic non-reciprocal dynamics.