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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]

Structural metamaterial with negative Poisson's ratio often has low stiffness due to its porous structure. For engineering applications, the various strategies have been developed to enhance its stiffness but also weaken the negative Poisson effect. In this work, we propose a 3D reinforced re-entrant structure (RRS) by adding arrow structures to the classical re-entrant structure (RS), which is fabricated by photocuring 3D printing of photosensitive resin. The structure-properties correlative mechanism of RRS is systematically analyzed by combining experiment (quasi-static compression experiment) and finite element simulation (ABAQUS). It is found that the equivalent elastic modulus and negative Poisson's ratio of RRS can be tuned by various structural parameters (i.e. the thickness ratio η, the length ratio of the slant rod α, the length ratio of the vertical rod β, and the angle θ of the re-entrant cells). By optimizing the structure parameters, the equivalent elastic modulus of RRS with the negative Poisson's ratio of −0.28 can be significantly increase to 13.67 MPa, which is 12.32 times larger than that of RS with the same negative Poisson's ratio. Due to the flexible design of stiffness and negative Poisson ratio, our proposed 3D reinforced re-entrant structural metamaterial provides a potential way for designing engineering materials with desirable performance. [ABSTRACT FROM AUTHOR]

Ti2 Nb 1 0 O 2 9 (TNO) is considered as a potential anode material due to its high capacity/power density and reliable safety. However, its poor electronic conductivity restricts its rate performance, which is important for its application in electric vehicles (EVs). In this study, we fabricated a hybrid of Ti2 Nb 1 0 O 2 9 − x /holey-reduced graphene oxide (TNOx/HRGO) by a two-step method. In the structure of TNOx/HRGO, TNOx microspheres with oxygen vacancies are wrapped by gossamer-like HRGO. The oxygen vacancies of TNOx and the high conductivity of HRGO can effectively enhance the electronic conductivity of the TNOx/HRGO hybrid, and the HRGO holes are beneficial for the transmission of lithium-ion ( Li + ). The synergy effect of above features improves the rate performance of the TNOx/HRGO hybrid. In addition, the existence of HRGO can buffer volume expansion during the insertion processes of Li + , which can improve cyclic stability of the TNOx/HRGO hybrid. Consequently, the TNOx/HRGO electrode has excellent lithium-ion storage capacity, with high-rate performance (242 mAh/g at 10∘C, 225 mAh/g at 20∘C and 173 mAh/g at 40∘C) and excellent cyclic stability (98.0% capacity retention after 300 cycles at 10∘C). This work reveals that TNOx/HRGO can be a potential anode material for high-rate-performance lithium-ion storage. TNOx/HRGO hybrid was fabricated through solvothermal method, annealing, and freeze-drying, and its performance as anode of LIB was investigated. Due to its porous microstructure, the existence of oxygen vacancies and holey-reduced graphene oxide coating, the electronic conductivity and ionic conductivity of TNOx/HRGO were greatly improved, thus obtaining excellent high-rate performance. [ABSTRACT FROM AUTHOR]

Although bulk superhydrophobic materials are considered as promising candidates because of their durable anti-wetting properties, they still face some challenges such as complicated fabrication processes and inherent brittleness. In the present study, we prepared a robust and flexible bulk superhydrophobic film by a facile “UV curing + solvent evaporation” method. Using this method, a cross-linked organic gel is generated by rapid thiol–ene photopolymerization (within 60 s) of a polydimethylsiloxane (PDMS)/hydrophobic silica/cyclohexane suspension and is further transformed into a superhydrophobic porous film after solvent evaporation. With the optimized solvent/polymer mass ratio (15 : 1), the superhydrophobic PDMS/silica film shows high stretchability (∼68%) and solid mechanical strength because of the appropriate cross-linking degree and low porosity of the polymer skeleton. The silica particles and porous structure cooperatively form self-similar and hierarchical structures across the film bulk, which can be repetitively exposed to the surface by abrasion to maintain durable superhydrophobicity. Consequently, the robustness and regenerative characteristics of the hierarchical structure enable the film to maintain durable superhydrophobicity while facing various mechanical damages such as 1000 cycles of stretching–releasing and 500 abrasion cycles. Taking advantage of the regenerative characteristics, the damaged superhydrophobic film surface is rapidly recovered by sanding treatment without the use of healing agents. [ABSTRACT FROM AUTHOR]

Although superhydrophobic porous membranes are considered to be very promising candidates for oil–water separation, their fabrication methods often involve complicated treatments to build a coating with micro/nano-features on a porous mesh (called “coating on a mesh structure”), which can lead to weak mechanical stability of the superhydrophobic surfaces and the formation of inhomogeneous membrane pores. Herein, we report a facile and environmentally friendly 3D printing approach to fabricate superhydrophobic membranes with an ordered porous structure for oil–water separation using hydrophobic nanosilica-filled polydimethylsiloxane (PDMS) ink. The addition of nanosilica can improve the mechanical strength of the ink and thus ensures the formation of desired topographical structures without the risk of collapsing during 3D printing. Through adjusting the geometrical parameters, a superhydrophobic PDMS membrane was obtained, which mainly depended on the roughness at the sub-millimeter scale. More importantly, the 3D printing approach described herein integrated the superhydrophobic surface into the porous framework and resulted in a mechanically durable superhydrophobic membrane, which successfully avoids the weak interface adhesion issue that arises from the traditional “coating on a mesh structure.” Moreover, the pore size of the printed membrane could be easily adjusted via a computer program to optimize both the liquid flux and separation efficiency of the membranes. The maximum oil–water separation efficiency (∼99.6%) could be achieved for the printed porous membrane with the pore size of 0.37 mm, which also exhibited a high flux of ∼23 700 L m−2 h−1. [ABSTRACT FROM AUTHOR]

SERS optrodes were used to “fish” aqueous drops from superhydrophobic surfaces. The technique led to an improvement of 2–3 orders of magnitude in the lowest detectable amount of the Raman probe nile blue A, reaching 25 fg (34 attomoles). Further tests run on samples containing pesticide revealed that 20 pg of triazophos could be clearly detected from a single drop. [ABSTRACT FROM AUTHOR]

This paper presents an efficient and simple processing method for the fabrication and regulation of nano-scale wrinkle patterns. The stiff film is created through cross-linking the surface of ultrathin polymer film within twenty nanometers by using the hyperthermal hydrogen induced cross-linking (HHIC) method, and then the bilayer is heated above the glass transition temperature of the polymer before quenched to room temperature. In this way, wrinkle patterns with wavelength ranging from 150 to 300 nm are prepared. And a morphology transition between the pattern of single points (convex bumps) and the pattern of ridges (labyrinth) is observed. The formation of wrinkle patterns is systematically investigated as functions of the thickness of original ultrathin film, the time of HHIC treatment, the annealing temperature and the chemical structure of polymers. Furthermore, nano-patterned silicon wafer is used as a template to create multiscale, anisotropic wrinkle patterns. [ABSTRACT FROM AUTHOR]

A surface enhanced Raman scattering (SERS) substrate, capable of extracting small amounts of organic species from surfaces of different types of materials with variable roughness, has been fabricated. The substrate consists of Ag NPs encapsulated in poly(vinyl alcohol) (PVA) hydrogels, commonly known as PVA “slime”. Unlike traditional SERS substrates, such as colloidal suspensions, the resulting PVA slime SERS substrate presents good viscoelasticity, allowing it to conform to the surface of various materials of arbitrary roughness. Surfaces of different materials, including sandpapers, cotton, metal, and wood, previously contaminated with nile blue A (NBA) were analyzed with the PVA slime SERS substrate. Limits of detection (LOD) as low as 100 ppb (0.79 ng in a total amount on an area of ∼3 cm2) were achieved for all surfaces tested. Pesticides and Sudan red III on the glass surface have also been detected, with a LOD of 1.6 ng per ∼3 cm2. [ABSTRACT FROM AUTHOR]

Enhancing the electrolyte wetting of separators by surface modification is very critical to prepare highperformance lithium-ion batteries. Herein, we present a new approach named hyperthermal hydrogen induced cross-linking (HHIC) technology to increase the electrolyte-affinity of polypropylene (PP) separators by covalently cross-linking a thin layer of poly(ethylene oxide) (PEO) on surface-inert PP separators. With the HHIC treatment, the polar functionalities of PEO (e.g. -OH, C-O-C) can be preserved through selective cleavage of C-H bonds and subsequent cross-linking of resulting carbon radicals generated on PEO and PP chains. As proved by solvent rinsing tests, contact angle measurements and Fourier transform infrared spectroscopy, a PEO coating was found firmly fixed on the separator surface, which results in significantly improved wetting with the electrolyte. Electrochemical measurements on subsequent lithium-ion batteries with the modified separator by HHIC treatment exhibit a lower internal resistance but higher capacity retention when compared to the pristine separator. HHIC treatment is concluded to be a highly efficient and environmental-friendly approach for separator surface modification without need for other chemical additives (e.g. chemical cross-linkers, initiators, and catalysts) and can preserve the desired macroscopic material properties of separators such as pore structures and mechanical strength. [ABSTRACT FROM AUTHOR]