Abstract
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•A dual-stage photocrosslinked polymer network for advanced manufacturing was developed.•Complex 2D/3D structures can then be programmed into other desired, permanent shapes.•The mechanical performance was significantly increased after the second curing step.•The fabricated superhydrophobic micropatterns can be molded with different curvatures.
We report a dual-stage photocrosslinked polymer network based on sequential ultraviolet (UV)-triggered radical polymerization and thermally activated etherification, applicable to the fabrication of tailorable and programmable high-resolution structures. The first stage involves photoinitiated polymerization of monomer and crosslinker to obtain an intermediate polymer network. As such, sophisticated two-dimensional (2D) and micro-scale three-dimensional (3D) structures can be made by using UV-based advanced manufacturing technologies. These complex structures can then be readily programmed into other desired, permanent shapes, in the second stage, via thermally triggered etherification which results in a highly crosslinked, robust polymer network. The intermediate network (Stage I) is characterized to have a Young’s modulus ranging from 342 to 1146 MPa and a glass transition temperature from 52 °C to 83 °C, depending on the concentration of crosslinker. The same material attains a glass transition temperature ranging from 67 °C to ~105 °C and a Young’s modulus of up to 1607 MPa after the subsequent heating process (Stage II). Originally 3D printed 2D structures can be further programmed into rigid, permanent 2.5/3D ones. Micropatterns fabricated from intrinsically hydrophilic dual-stage crosslinked photopolymers through soft lithography show superhydrophobicity, and can subsequently be molded with different curvatures for practical applications.