The influence of printing parameters on multi-material two-photon polymerisation based micro additive manufacturing

Abstract

Two-photon polymerisation (2PP) based additive manufacturing has emerged as a powerful technology to fabricate complex three-dimensional micro- and nanoscale architectures. However, a comprehensive understanding of the effect of printing parameters on the functional properties of these structures is needed to unleash the potential of 2PP and enable controlled deposition / integration of various materials into multi-material structures. In this study we investigate the correlation between printing parameters, resin composition and the final properties of 2PP structures fabricated with different monomers and initiators. The link between 2PP process and final material properties is validated by morphological studies, vibrational spectroscopy and advanced mass spectrometry, ToF-SIMS, imaging. We establish empirical relationships between printing parameters and mechanical properties, and achieve controlled deposition of different monomers with high precision and uniform composition. The approaches developed here are successfully used to demonstrate multi-material 2PP and produce complex 3D architectures incorporating three polymers. The 2PP structures produced can be transferred into solution or onto different substrates, in addition to direct fabrication on flexible substrates. This work advances the understanding of the 2PP process, which enable rational design and manufacture of complex geometries and additive manufacturing of nanoscale multi-material structures.