Programmable solvent-responsive PDMS microstructures via 3D direct laser writing

This study addresses the three-dimensional (3D) fabrication of polydimethylsiloxane (PDMS) for intelligent micromechanical systems through a novel PDMS-based photoresist compatible with two-photon polymerization (2PP). By optimizing a 2PP system, photosensitivity and processability were significantly enhanced, enabling complex 3D structures with sub-micron precision. Using programmable 2PP direct laser writing (DLW) and by controlling the processing parameters and scanning strategies, we established a quantitative model for structural fidelity and achieved spatial control over the crosslinking density. Thus, solvent-responsive components used for encrypted micropillar arrays and smart microvalves were successfully fabricated, demonstrating the precise and controllable deformation upon solvent stimulation. Excellent cytocompatibility is also confirmed by biocompatibility tests. This research breaks through conventional PDMS microfabrication limitations, providing innovative material solutions and processing pathways for intelligent micro-systems in soft robotics and biomedical fields.