Size control of shape switchable micronetworks by fast two-step microfluidic templating

Shape-memory polymer micronetworks (MN) are micrometer-sized objects that can switch their outer shape upon external command.This study aims to scale MN sizes to the low micrometer range at very narrow size distributions. In a two-step microfluidic strategy, the specific design of coaxial class capillary devices allowed stabilizing the thread of the dispersed phase to efficiently produce precursor particles in the tip-streaming regime at rates up to similar to 170 kHz and final sizes down to 4 mu m. In a subsequent melt-based microfluidic photocrosslinking of the methacrylate-functionalized oligo(epsilon-caprolactone) precursor material, MN could be produced without particle aggregation. A comprehensive analysis of MN properties illustrated successful crosslinking, semi-crystalline morphology, and a shape-switching functionality for all investigated MN sizes (4, 6, 9, 12, 22 mu m). Such functional micronetworks tailored to and below the dimension of cells can enable future applications in technology and medicine like controlling cell interaction.

Automated summary

This study successfully scaled the sizes of shape-memory polymer micronetworks to the low micrometer range with very narrow size distributions. A two-step microfluidic strategy involving specific design of coaxial class capillary devices allowed for efficient production of precursor particles in the tip-streaming regime, leading to final sizes down to 4 μm. Subsequent melt-based microfluidic photocrosslinking of the precursor material enabled the production of micronetworks without particle aggregation, showing successful crosslinking, semi-crystalline morphology, and shape-switching functionality for all investigated sizes.