Hydrophobic surface for direct PEGDA micro-pattern fabrication

Photopolymerization of hydrogels films has gained interest in many biomedical and industrial fields. Hydrogel micro-patterns fabricated directly on a device are used as filtering barriers, however, due to weak mechanical properties, these parts require a stable support but deposition of hydrogel in non-polymerized state brings a risk of sinking inside the structure. These limitations can be overcome by applying a hydrophobic surface. This paper presents a novel two-step method, in which a hydrophobic surface was designed and manufactured using mask-projection vat photopolymerization additive manufacturing (VPP). Afterwards, PEGDA-based hydrogel photopolymers were deposited on the surface and a micro-scale patterns were cured. The parts were subjected to water immersion and heating in order to evaluate the swelling and shrinking behaviour of hydrogel. The parts remained stable on the substrate and maintained the properties and the results revealed the shape retention over 97%. This work shows that VPP can be applied in the manufacturing of hydrophobic surfaces for hydrogel photopolymer deposition and curing without sacrificing critical properties. Graphical Abstract: [Figure not available: see fulltext.]