Digital Light Processing (DLP) 3D Printing Fabrication of Hydrophobic Meshes Incorporating Fluorinated and Silicone-Based Acrylates Combined with Surface Engineering: Comparison of Their Oil–Water Separation Efficiency

Hydrophobic materials have been fabricated by DLP vat photopolymerization of isobornyl acrylate-based resins with chemical modification and/or surface geometry engineering. Fluorinated and polydimethylsiloxane (PDMS)-based acrylic monomers are used for chemical modification and are incorporated into the printed materials. The water wettability was significantly reduced and plateaued with as low as 5% (w/w) of the auxillary hydrophobic monomer. Regarding surface geometry, meshes with different pore sizes are 3D printed, and the surface hydrophobicity increased with the pore size. We compare the oil-water separation efficiency of the 3D-printed meshes hydrophobized by these three approaches. It was found that the isobornyl acrylate-based resin already demonstrated separation at the optimum pore size. Modification with PDMS showed a further improvement in separation efficiency, whereas no significant increase was observed by use of the fluorinated monomer. This highlights that careful design of surface geometry should be considered to avoid the use of environmentally unfriendly and potentially toxic chemicals when making hydrophobic materials.