Method for preparation, programming, and characterization of miniaturized particulate shape-memory polymer matrices.

Their capability to change their shape on demand has created significant interest for shape-memory polymers (SMPs) in minimally invasive surgery. To evaluate the miniaturization of SMP matrices for small-sized implants or controlled release systems, a strategy to prepare and evaluate microsized SMP model particles is required. This methodological study reports the emulsion-based preparation of ~30 μm microparticles (MPs) from a phase-segregated SMP, poly(ε-caprolactone) [PCL] and poly(ω-pentadecalactone) [PPDL], with a particular focus on the effects of process parameters such as polymer solvents or stabilizer type/concentration on formation and size distribution of SMP MPs. Processes for the preparation of SMP MP-loaded water-soluble polymer films with tailored mechanical properties were developed and applied for programming the SMP MP to a temporary ellipsoid shape by film stretching. For the functional evaluation of shape recovery of MPs, a light microscopy-based setup with temperature control is proposed by which the stimuli-induced switching of the microsized SMP matrices could be confirmed. Overall, by applying this methodological strategy to various thermoplastic SMPs, a routine to identify and characterize the microscale functionality of SMPs in miniaturized applications will be broadly accessible.