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Three-dimensional-printed silicone rubber foams, with their designable and highly ordered pore structures, have shown exceptional potential for engineering applications, particularly in areas requiring energy absorption and cushioning. However, optimizing the mechanical properties of these foams through structural design remains a significant challenge. This study addresses this challenge by formulating the research question: How do different 3D-printed topologies and printing parameters affect the mechanical properties of silicone rubber foams, and how can we design a novel topological structure? To answer this, we explored the mechanical behavior of two common structures–simple cubic (SC) and face-centered tetragonal (FCT)–by varying printing parameters such as filament spacing, filament diameter, and layer height. Furthermore, we proposed a novel two-level 3D-printed structure, combining SC and FCT configurations to enhance performance. The results demonstrated that the two-level SC-SC structure exhibited a specific energy absorption of 8.2 to 21.0 times greater than the SC structure and 2.3 to 7.2 times greater than the FCT structure. In conclusion, this study provides new insights into the design of 3D-printed silicone rubber foams, offering a promising approach to developing advanced cushioning materials with superior energy absorption capabilities. [ABSTRACT FROM AUTHOR]

Special wettability of biological surfaces usually depends on the unique micro-structures and surface chemistry natures. However, current preparation methods often involve complex processing steps or expensive moulds and have the limited ability to simulate these ordered and elaborate micro-structures. Herein, we report a facile and mould-free approach to fabricate special wetting surfaces by patterning an ordered porous structure with various geometric parameters via one-step 3D printing of Polydimethylsiloxane (PDMS) ink. By adjusting pore structure at sub-millimeter scale, the printed PDMS porous films can present versatile special surface wettabilities such as superhydrophobicity and anisotropic wettability. With the guide of computer program, water contact angles (WCAs) along parallel and perpendicular directionsand anisotropy wetting degree of the printed film can be tailored by controllingprinting speed and filament spacing. Through optimizing the geometrical parameters, a superhydrophobic PDMS filmwith a WCA of about 155° is obtained, which mainly depends on the sub-millimeter scale structure. The superhydrophobicity of the printed porous PDMS film also exhibits excellent durability against thermal aging. Our work demonstrates that the printed superhydrophobic porous film can be used for some attracting applications such as air-breathable water-proofing, water-repellent floating carrier, and no-loss liquid transfer. [ABSTRACT FROM AUTHOR]