Surface Energy-Confined Multi-Layer Inkjet Printing for Customizable Optical Microstructures.

Abstract

Inkjet printing emerges as a versatile on-demand patterning technique for additive manufacturing of optical microstructures, yet its ability to regulate the ink droplet morphology is constrained by the intrinsic interplay between ink-substrate wetting conditions, thereby hindering the customizable fabrication of 3D microstructures. Here, a surface energy-confined multi-layer inkjet printing strategy is developed for precisely fabricating curved optical microstructures with tunable size, solid angle, and configuration. The strategy is implemented through custom-engineered layer-by-layer printing on a pre-patterned substrate with spatially defined interfacial energy barriers, enabling the precise construction and integration of distinct optical microdomes (characterized by substrate attachment and uniform curved profiles) at the microscale. Notably, the strategy facilitates the high-throughput printing of diverse topological microdomes, ranging from triangular to hexagonal architectures. The as-fabricated microdomes, featuring precisely engineered morphology and sub-nanometer surface roughness, exhibit integrated light-field manipulation capabilities and unique multifocal characteristics, highlighting their potential for miniaturized optical systems and intelligent imaging devices. Beyond UV-cured polymers, this methodology is extendable to nanomaterial-based micro-3D printing (e.g., colloidal photonic crystal microdomes), opening avenues for more sophisticated optical functionalities. As a proof-of-concept demonstration, a non-imaging multidimensional encryption platform is printed leveraging 3D morphology-tailored optical readout.