Three-Dimensional Coffee-Ring Effect Induced Deposition on Foam Surface for Enhanced Photothermal Conversion

Uniformly depositing a thin layer of functional constituents on porous foam is attractive to realize their concentrated interfacial application. Here, a simple but robust polyvinyl alcohol (PVA)-mediated evaporation drying strategy to achieve uniform surface deposition on melamine foam (MF) is introduced. Solutes can be accumulated homogeneously to the surface periphery of MF due to the enhanced coffee-ring effect of PVA and its stabilizing effect on various functional constituents, including molecules and colloidal particles. The deposition thickness is positively correlated with the feeding amounts of PVA but seems to be independent of drying temperature. 3D outward capillary flow driven by the combination of contact surface pinning and continual interfacial evaporation induces the forming of core-shell foams. The enhanced interfacial photothermal effect and solar desalination performance using PVA/polypyrrole-coated MF as a Janus solar evaporator are demonstrated.

Top-up fabrication of gold nanorings

A simple method for the fabrication of gold nanorings with reliable material composition and reproducible morphology that relies on a combination of top-down and bottom-up techniques is presented. Here, lithographically defined hole arrays are used as templates for the deposition of gold nanoparticles. The resulting gold nanoparticle rings are joined by electroless deposition of gold, thereby leading to the formation of gold nanoring arrays that show plasmonic resonance in their optical spectra at theoretically predicted wavelengths. In addition, the gold nanorings can be released from the template by extensive rinsing with water, thereby enabling their further functionalization or assembly and the re-use of the template for the preparation of more nanorings.

A simple route to hierarchically assembled micelles and inorganic nanoparticles

Earning their stripes: A hierarchical assembly of micelles composed of an amphiphilic diblock copolymer, poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP), were made by combining controlled evaporative self-assembly of the confined PS-b-P4VP toluene solution in a cylinder-on-Si geometry with spontaneous self-assembly of micelles. This method gave microscopic stripes of nanometer-sized PS-b-P4VP micelles within the stripes (see pictures).