Fabrication of Nanostructured Polymer Composites

The composite materials were fabricated according to reported protocols.^25,26 (link) First, a 50% (w/w) solution of styrene–ethylene–butylene–styrene (SEBS) block copolymer (G1645, Kraton LLC) in toluene (Fisher Chemical) was spin-coated onto the silicon wafer-bound nanostructured Cu films. Next, the resulting nanostructured composites were heat-treated at 60 °C for 10 min. to remove any residual solvent. Last, the nanostructured composites with typical thicknesses of ∼30 μm were manually delaminated (detached) from the substrate as free-standing materials by means of an attached plastic frame. The composites lacking planar Cu layers were fabricated by chemically etching free-standing nanostructured composites with a 0.2% FeCl₃ solution (Fisher Scientific).³² (link) The composites lacking Cu nanostructures were fabricated from planar Cu layers on silicon wafers. The SEBS polymer matrices (films) were fabricated by spin-coating SEBS solutions directly onto clean silicon wafers. The composite materials obtained via these procedures were characterized with digital camera imaging, SEM imaging, tensile testing, infrared spectroscopy characterization, and stability testing.