Work

Enhanced adhesion of high-resolution two-photon polymerization 3D-printing: a quantitative study on substrate treatments and process compatibility for microfabrication

Year: 2026

Type: article

Abstract: Two-photon polymerization (2PP) is a high-resolution 3D printing technology that enables the fabrication of complex micro- and nanostructures with sub-micrometer precision. While 2PP offers geometric freedom for applications in microfluidics, photonics, and micro-electromechanical systems (MEMS), the limited adhesion of printed structures to common substrates remains a critical bottleneck to increase its use in process with multiple steps. The objective of this work is to identify substrate treatments capable of maintaining strong adhesion throughout representative microfabrication processes. This study quantitatively evaluates the adhesion force of 2PP-printed microstructures on four substrate types, plasma-activated silicon, ITO-coated glass, silane-functionalized silicon, and SU8-coated silicon, using lateral shear testing. We investigate the influence of geometry, thermal and solvent exposure on adhesion performance. Among studied parameters, it revealed that cylindrical structures exhibit superior adhesion compared to cubic ones due to reduced residual stress concentrations. Our results demonstrate that silanization improve adhesion force, but its stability is compromised under solvent exposure, contrary to expectations. In contrast, SU8 interlayers provide robust adhesion retaining significant adhesion force even after thermal and chemical stress. These findings establish practical design guidelines for integrating 2PP structures into microfabrication workflows.

Source: Additive Manufacturing Letters

DOI: 10.1016/j.addlet.2026.100415