3D Printed Parahydrophobic Surfaces as Multireaction Platforms

Abstract

Parahydrophobic surfaces (PHSs) composed of arrays of cubic μ-pillars with a double scale of roughness and variable wettability were systematically obtained in one step and a widely accessible stereolithographic Formlabs 3D printer. The wettability control was achieved by combining the geometrical parameters (H = height and P = pitch) and the surface modification with fluoroalkyl silane compounds. Homogeneous distribution of F and Si atoms onto the pillars was observed by XPS and SEM-EDAX. A nano-roughness on the heads of the pillars was achieved without any post-treatment. The smallest P values lead to surfaces with static contact angles (CAs) >150° regardless of the H utilized. Interestingly, the relationship 0.6 ≤ H/P ≤ 2.6 obtained here was in good agreement with the H/P values reported for nano- and submicron pillars. Furthermore, experimental CAs, advancing and receding CAs, were consistent with the theoretical prediction from the Cassie–Baxter model. Structures covered with perfluorodecyltriethoxysilane with high H and short P lead to PHSs. Conversely, structures covered with perfluorodecyltrimethoxysilane exhibited a superhydrophobic behavior. Finally, several aqueous reactions, such as precipitation, coordination complex, and nanoparticle synthesis, were carried out by placing the reactive agents as microdroplets on the parahydrophobic pillars, demonstrating the potential application as chemical multi-reaction array platforms for a large variety of relevant fields in microdroplet manipulation, microfluidics systems, and health monitoring, among others.

Biomimetic Superhydrophobic Materials through 3D Printing: Progress and Challenges

“…Under some circumstances, the 3D printed objects alone cannot realize superhydrophobicity due to the high surface energy and, in consequence, post-modification of these objects is of vital importance. One common modification method is coating hydrophobic materials onto the surfaces [ 34 , 35 , 36 , 120 , 121 , 122 , 123 , 124 , 125 ]. Motivated by hierarchical structures of rice leaf, Palza et al firstly printed microchannels with intrinsic roughness by the SLA method, then the surface was modified by TiO 2 nanoparticles [ 34 ] ( Figure 8 a).…”

Fabrication of Superhydrophobic Polycaprolactone Foam via Phase Separation and Silica Modification for Oil–Water Separation

“…[5] Nonetheless, these techniques continue to face challenges, such as limited separation efficiency, secondary pollution concerns, elevated energy consumption, and substantial costs, significantly impeding their broader, practical-scale implementation. [6] In recent years, a variety of novel porous materials characterized by hydrophobic properties have been developed to achieve efficient oilwater separation. These materials include aerogels, [7] foams, [8][9][10][11] DOI: 10.1002/macp.202300436 microspheres, [12,13] and membranes.…”

Superhydrophobic Thermoplastic Polyurethane Foam Fabricated by Phase Separation and Silica Coating for Oil‐Water Separation

“…[1][2][3] The application of conventional techniques for oil removal, such as biological treatment [4,5] and burning, [6] is often associated with high costs, low efficiency, and secondary pollution. [7] Recent years, many researchers have turned to nature-inspired hydrophobic material to develop oil-water separation materials with unique wetting properties, such as aerogels, [8,9] polymer foams, [10][11][12][13] cotton fabric, [14] microspheres, [15][16][17] and bundles, [18,19] that could selectively adsorb oil with less water adsorption. Not only in the field of oilwater separation, materials with special wettability also find applications in self-cleaning water collection and other areas.…”