Self-assembled monolayer enhanced support-free two-photon polymerisation for microscale kinematic pairs

This study introduces a novel support-free two-photon polymerization (TPL) method using a tailored TPEO photoresist to fabricate dynamic microscale structures with high precision and stability. The TPEO photoresist's high yield stress and shear viscosity ensure structural integrity, while a self-assembled monolayer reduces surface friction by 69%, enhancing motion between components. The technique achieves a minimum clearance of 2.5 μm for kinematic pairs and demonstrates potential in creating bio-inspired hair follicle structures and complex assemblies. Despite its advantages, the method requires further development for improved printing accuracy and gap precision in dynamic micro-machines.