Surfaces are how bulk materials interact with the world, and in nature, how organisms interact with their environment. As such, multiple approaches in water-securing research take inspiration from unique water-surface interactions observed in numerous plants and animals that address scarcity. Traditional strategies used for surface formation (e.g. photolithography, block copolymer assembly, additive manufacturing, and machining) have certain limitations, including the need for multiple processing steps or specialized equipment, patterned length scale restrictions, as well as requirements for niche chemical precursors. These limitations have associated costs in terms of time, energy, and resources, also resulting in excess waste generation. Compared to traditional methods, photopolymerization induced phase separation (PIPS) offers many advantages by utilizing commercially available chemicals and operating at ambient conditions to form features at multiple length scales in a single UV cure step with no photomasks and minimal waste generation. Here, the Namib Desert beetle is taken as a guide for designing surfaces capable of water capture from humid environments. The chemical and physical patterning that arises from PIPS makes it ideal for designing complex, hierarchically-structured surfaces reminiscent of the beetle carapace. In this biomimetic design, surface wrinkling and phase separation behavior are studied in conjunction with one another, combining mechanisms often studied in isolation. Two families of PIPS resins were studied: (1) an acrylonitrile and 1,6 hexanediol diacrylate comonomer system with poly(methyl methacrylate) additives, and (2) a vinyl acetate and 1,6 hexanediol diacrylate comonomer system with poly(dimethyl siloxane) additives. The inert polymer additives were initially dissolved in the comonomer solutions where, upon photopolymerization, decreased miscibility between these inert additives and the developing polymer network triggered phase separation. Examining the effects of comonomer/polymer selection, crosslink density, UV intensity, and curing environment provide a robust exploration space for investigating the interplay of phase separation, network vitrification, and interfacial energies present in the system. Control over reaction thermodynamics and kinetics through these experimental variables resulted in heterogeneous polymer morphologies with unique chemical and physical surface patterning on both the microscale and macroscale. Specifically, inert polymer additives enable macroscale wrinkles to form \textit{via} depth-independent internal stresses across phase domains, while simultaneous microscale roughness arises from depth-wise mechanical gradients from oxygen radical quenching. Phase separation drives chemical patterning, with domain formation and coalescence induced by tailoring interfacial energy interactions of the system, to form macroscale regions with differing wettabilities. Introducing materials with contrasting surface energies to form resin-material interfaces can spatially direct the chemical domains as the system reorients to minimize its surface energy. Using the acrylonitrile and 1,6 hexanediol diacrylate comonomer system with poly(methyl methacrylate) additives, samples faces were produced that had stark contrasts in water contact angles, with a difference of over 50^o is observed between the hydrophilic and hydrophobic faces.To better understand PIPS systems, a systematic approach using Hansen Solubility Parameters (HSP) enabled rapid screening of potential resin formulations. The evolving miscibility interactions between the resin components during photopolymerization (reacting monomer to inert polymer, reacting polymer to inert polymer, and reacting monomer to reacting polymer) were evaluated. Experimental data from the acrylonitrile system was used to benchmark predictions in using this approach. This screening afforded by HSP analysis allowed for the design of a vinyl acetate and 1,6 hexanediol diacrylate comonomer system with poly(dimethyl siloxane) additives, minimizing safety hazards while maintaining comparable versatility in chemical and physical patterning. These resins were used to form large scale (100 cm^2) coatings to test for water capture performance. Here, hydrophilic domains were formed through resin-water interfaces introduced at the start of photopolymerization, resulting in circular smooth domains amid roughened hydrophobic domains; patterning similar to the Namib Desert beetle. Hydrophobic PIPS surfaces with wrinkles demonstrated higher volumes of water collection compared to plain glass controls, and surfaces with chemically and physically heterogeneous domains collected the most water. This work aims to showcase the versatility of single step coating design through PIPS to produce complex chemically and physically patterned surfaces using materials that possess minimal hazards while still being commercially and economically viable.
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