Collapsing and bundling of wet nanostructures can be a desirable or an unwanted phenomenon depending on the target application. We study the effect of the aspect-ratio and solvent surface tension on bundling of Pt-based metallic glass nanowires prepared by thermoplastic molding. The results show that the bundling can be quantitatively described by the competition between the Laplacian capillary force and the elastic restoring force. Supercritical CO2 drying can prevent bundling to form vertically aligned metallic glass nanowires with high aspect-ratios (>15). Optical measurements and simulations reveal that the diffuse reflectance of metallic glass nanowires strongly depends on their profile (vertical or bundled).

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A simple method for the fabrication of stable and highly active surface enhanced Raman scattering (SERS) substrate by exploiting the optical properties of the silver nanoparticles (AgNPs) and organizational characteristics of the polymer is presented. Homogeneous distribution of AgNPs is achieved with the usage of poly (4,7-di-2,3-dihydrothieno [3,4-b] [1,4] dioxin-5-yl-2,1,3 benzoselena diazole) (PESeE) film coated on the indium tin oxide glass (ITO) surface. The obtained structure ensured the emergence of a large number of hot spots where the localization of electromagnetic energy can result in enhancement of the Raman signal. The effect of the PESeE film thickness, the density of AgNPs added to the polymer film, and the concentration of silver ion solution on the morphology of the substrate and the enhancement of the SERS signal was revealed by using field emission scanning electron microscopy (FE-SEM) and SERS measurements. Enhancement power, homogeneity, and stability of the PESeE-AgNPs substrate were also investigated with measurement of the Raman probe. Spot-to-spot and batch-to-batch reproducibilities of the prepared substrate were calculated as 8.4%, and 10.2% (RSD %) respectively. Due to these properties, PESeE-AgNPs SERS substrate can be a good candidate for the detection and sensor application of various biological and chemical analytes.

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Materials with large photo-thermal energy conversion efficiency are essential for renewable energy applications. Photo-excitation is an effective approach to generate controlled and localized heat at relatively low excitation optical powers. However, lateral heat diffusion to the surrounding illuminated areas accompanied by low photo-thermal energy conversion efficiency remains a challenge for metallic surfaces. Surface nanoengineering has proven to be a successful approach to further absorption and heat generation. Here, we show that pronounced spatial heat localization and high temperatures can be achieved with arrays of amorphous metallic glass nanorods under infrared optical illumination. Thermography measurements revealed marked temperature contrast between illuminated and non-illuminated areas even under low optical power excitation conditions. This attribute allowed for generating legible photo-induced thermal patterns on textured metallic glass surfaces.