Though beam-based lattices have dominated mechanical metamaterials for the past two decades, low structural efficiency limits their performance to fractions of the Hashin-Shtrikman and Suquet upper bounds, i.e. the theoretical stiffness and strength limits of any isotropic cellular topology, respectively. While plate-based designs are predicted to reach the upper bounds, experimental verification has remained elusive due to significant manufacturing challenges. Here, we present a new class of nanolattices, constructed from closedcell plate-architectures. Carbon plate-nanolattices are fabricated via two-photon lithography and pyrolysis and shown to reach the Hashin-Shtrikman and Suquet upper bounds, via in situ mechanical compression, nano-computed tomography and micro-Raman spectroscopy. Demonstrating specific strengths surpassing those of bulk diamond and average performance improvements up to 639% over the best beam-nanolattices, this study provides detailed experimental evidence of plate architectures as a superior mechanical metamaterial topology.

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A fast method for detecting pharmaceutical drugs, such as paracetamol, by surface-enhanced Raman spectroscopy (SERS) using a gold nanoparticle substrate was studied.

We report the dynamic behavior of surface-enhancement Raman scattering (SERS) spectra using rhodamine 6G dye (R6G, 10–8 mol L–1) adsorbed on gold nanorods (AuNRs). SERS spectra displayed a strong time-dependence intensity in wet to dry transition states. FEG-SEM images reveal a stacking of AuNRs organization that can lead to Raman signal improvements due to the formation of a 3D hot spot matrix that acts as a trap for target molecules. AuNRs nanostructured films were efficiently employed to form SERS substrates. The independent random AuNR organization in the SERS spectra exhibits a characteristic profile of intensities due to different dielectric environmental conditions. Despite the variations observed in the spectra array, a pattern was recognized by statistical analysis. Multidimensional analysis ensured the distinction of the study’s requirements applied to the SERS response, exhibiting a silhouette coefficient of 0.92 with the least-squares projection technique. Changes in the SERS spectra profile from wet to dry state conditions of R6G dye solution can be interpreted as the dynamic behavior of R6G molecules correlated to distinct molecular adsorption and (or) surface distribution of the R6G molecules proving different plasmonic resonances. Simulations obtained from BEM calculation in experimental data corroborate that the SERS enhancement is strongly dependent on the nanoparticle coupling in nanoscale and the dielectric environment.

Electrochemical water splitting is one of the most promising technologies that could meet the increasing energy consumption requirements for the development of the human societyThe stability of electrocatalysts grown on substrates is a significant challenge for the construction of 3-dimensional (3D) stainless-steel (SS)-based electrodes for highly efficient water splitting. This paper presents an efficient and universal process to enhance the interfacial interaction between SS and highly active electrocatalysts for the preparation of 3D electrodes through the formation of an interfacial network of carbon nanotubes (CNTs) on the SS. Nanoscale X-ray computed tomography and focused ion beam are used to visualize the interface between CNTs and SS, and 3D structure of CNT/SS electrodes. The strongly interconnected CNTs network increases the surface area of the SS support that benefits the modification of highly active electrocatalysts and also serves as an electron/charge-conductive highway between electrocatalysts and support. The electrocatalysts on CNT/ SS further improve hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances, respectively, of the 3D electrodes. While compared to the SS-based electrodes reported recently, Pt/OxCNT/SS shows the best HER activity over wide pH range and RuO 2 /OxCNT/SS exhibits a comparable OER performance in neutral and alkaline electrolyte. An efficient approach is reported to combine highly active electrocatalysts with SS for the preparation of active and stable 3D electrodes that can be further explored in various areas.