Polymeric microdevices with bioinspired multifunctional
features
like defined geometrical actuation or spatially segregated surface
properties are attractive with potential applications in sensors,
microfluidic systems, on-demand carriers, and biomedical devices.
In this regard, here, we aim at enhancing the programability of multi-shape
memory micro-objects using atomic force microscopy (AFM) to achieve
a sequential shape reconfiguration or actuation at different geometrical
levels on demand. Temperature-memory polymer-based microcuboids were
designed and fabricated as a model system. The first step in the programing
of the microcuboids was achieved by compression between glass slides
with external force at selected programing temperatures T
p. Then, microbowls were generated by AFM nanoindentation
using a spherical tip on the surface of the microcuboids to create
temporary nanocavities at different T
p,inds. The geometry and surface structure of the microcuboids was analyzed
by AFM height images. By varying T
p/T
p,inds and the sequence of the procedure, multiple
nanocavities can be generated on the same microbowl to achieve sequential
full recovery and actuations of 2–6%. In addition, a demonstration
of microbowl trapping and sequential elevating submicron particles
was performed to prove the concept of the on-demand carrier and release
system. The technology presented in this work can inspire future design
of multifunctional micro-objects in order to fulfill complex tasks
with shape reconfiguration or actuation functions on micro-/nanolevel.
