Two-Photon Polymerization Nanomanufacturing Based on the Definition–Reinforcement–Solidification (DRS) Strategy

Abstract

Femtosecond laser additive manufacturing based on two-photon polymerization performs a useful technique for fabricating high-precision 3D structures. However, poor mechanical strength and low processing efficiency brought by near polymerization threshold processing to achieve high accuracy are still urgent problems. In this work, a definition-reinforcement-solidification (DRS) processing strategy is proposed to solve the current problems, in which DRS processing includes three steps: utilize a near-threshold femtosecond laser to accurately define the surface profile of 3D structures, perform enhanced scanning on the above structure's inner surface with a high-power femtosecond laser to increase the mechanical strength, and rapidly solidify the inner unpolymerized resin through one exposure of ultraviolet light to improve the processing efficiency. Compared with conventional near-threshold point-by-point direct writing, microstructures fabricated by the DRS strategy for a given geometry and polymer have hardness and Young's modulus values increase to 154% and 199%, respectively, and exhibit a 10000% improvement in machining efficiency without the loss of processing accuracy. Arbitrary complex 3D microstructures can be implemented rapidly via this strategy. This work will inject new vitality into two-photon polymerization additive manufacturing.