Single-Layer Photopolymerization Process for the Rapid Fabrication of Nature-Inspired Multifunctional Films

Functionally engineered films with nature-inspired hierarchical microstructures have many potential applications in aerospace, marine, biomedical, and water collection/separation. Here, a fast and sustainable manufacturing method, single-layer photopolymerization (SLP), is presented for the production of such surfaces. In the novel SLP process, a single digital mask is used to generate spatiotemporal variations in light patterns and intensity to create films consisting of zero-dimensional (0D) to two-dimensional (2D) microstructures within seconds without any pre- or postprocessing. The mechanism underlying the proposed surface engineering technique is discussed, and the relationship between process parameters and microstructure morphology, including its shape, size, and distribution, is modeled. Mesoscale films with conical features are tested for substrate adhesion, scalability, and flexibility. The efficacy of the SLP process is validated by comparing the fabrication time, surface quality, and mechanical properties of the fabricated films with the traditional layer-based photopolymerization process. To demonstrate potential applications, three multidimensional surfaces are designed inspired by moth eye (0D), mosquitoes (1D), and shark skin (2D), and their effects on hydrodynamic properties are studied. Moreover, multimaterial films consisting of cactus-inspired dual-spine topology and beetle-inspired dual-wettability were fabricated. The SLP technology and the fabricated multifunctional films demonstrated in this study can be employed in many other advanced applications, such as drug delivery devices, antireflective coatings, drag-resistant surfaces, and fog-harvesting devices.