Surface‐enhanced Raman spectroscopy (SERS) is now widely used as a rapid and inexpensive tool for chemical/biochemical analysis. The method can give enormous increases in the intensities of the Raman signals of low‐concentration molecular targets if they are adsorbed on suitable enhancing substrates, which are typically composed of nanostructured Ag or Au. However, the features of SERS that allow it to be used as a chemical sensor also mean that it can be used as a powerful probe of the surface chemistry of any nanostructured material that can provide SERS enhancement. This is important because it is the surface chemistry that controls how these materials interact with their local environment and, in real applications, this interaction can be more important than more commonly measured properties such as morphology or plasmonic absorption. Here, the opportunity that this approach to SERS provides is illustrated with examples where the surface chemistry is both characterized and controlled in order to create functional nanomaterials.

Raman analysis of dilute aqueous solutions is normally prevented by their low signal levels. A very general method to increase the concentration to detectable levels is to evaporate droplets of the sample to dryness, creating solid deposits which are then Raman probed. Here, superhydrophobic (SHP) wires with hydrophilic tips have been used as supports for drying droplets, which have the advantage that the residue is automatically deposited at the tip. The SHP wires were readily prepared in minutes using electroless galvanic deposition of Ag onto copper wires followed by modification with a polyfluorothiol (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-1-decanethiol, HDFT). Cutting the coated wires with a scalpel revealed hydrophilic tips which could support droplets whose maximum size was determined by the wire diameter. Typically, 230 μm wires were used to support 0.6 μL droplets. Evaporation of dilute melamine droplets gave solid deposits which could be observed by scanning electron microscopy (SEM) and Raman spectroscopy. The limit of detection for melamine using a two stage evaporation procedure was 1 × 10(-6) mol dm(-3). The physical appearance of dried droplets of sucrose and glucose showed that the samples retained significant amounts of water, even under high vacuum. Nonetheless, the Raman detection limits of sucrose and glucose were 5 × 10(-4) and 2.5 × 10(-3) mol dm(-3), respectively, which is similar to the sensitivity reported for surface-enhanced Raman spectroscopy (SERS) detection of glucose. It was also possible to quantify the two sugars in mixtures at concentrations which were similar to those found in human blood through multivariate analysis.

26The wettability and hydrophobicity of super-hydrophobic (SH) meshes is greatly influenced 27 by their topographic structures, chemical composition and coating process. In this study, the 28 properties of copper and stainless steel meshes, coated with super-hydrophobic electrolessly 29 deposited silver were investigated. A new method to test the pressure resistance of super-30hydrophobic mesh was applied to avoid any deformation of mesh. Results showed that SH 31 copper mesh and SH stainless steel meshes with the same pore size have almost the same 32 contact angle and the same hydrophobicity. SH copper mesh with a pore size of 122 μm can 33 resist water pressure of 4900 Pa and a decrease of pore size of mesh can increase the pressure 34 resistance of SH copper mesh. The SH copper mesh modified with 0.1M HS(CH2)10COOH 35 solution in ethanol has a controllable water permeation property by simply adjusting the pH of 36 water solution. SH copper mesh shows super-oleophilicity with organic solvents and so with a 37 water contact angle of 0° and it can be an effective tool for organic solvents/water separation. 38The separation efficiency of SH copper mesh for separating mixtures of organic solvent and 39 water can be as high as 99.8%. 40 41