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This paper reports a simple electrodeposition technology that enables rapid production of large-area polymer nanocomposites with layered structures that mimic the nacreous layer of mollusk shells. Uniform, electrostatically stabilized gibbsite nanoplatelets with high aspect ratio are preferentially oriented parallel to the electrode surface when an external direct current electric field is applied. The electroplated ceramic films have uniform thickness, and the thickness can be controlled by adjusting the nanoplatelet concentration of the electroplating baths. Homogeneous, optically transparent nanocomposites are obtained when the interstitials between the aligned nanosheets are infiltrated with polymer. The resulting ceramic-polymer nanocomposites exhibit four-times higher tensile strength and nearly 1 order of magnitude higher modulus than pure polymer films. The covalent linkage between the nanoplatelets and the polymer matrix plays an important role in determining the mechanical properties of these biomimetic nanocomposites.

This paper reports a simple and scalable colloidal templating nanofabrication technology for generating periodic metallic nanopyramid arrays as electrodes for electrochemical surface-enhanced Raman spectroscopy (SERS). These periodic arrays of nanopyramids with nanoscale sharp tips and high tip density can enhance the local electromagnetic field in the vicinity of the nanotips, resulting in high SERS enhancement (on the order of 10 6 ). The effect of the applied electrode potential and the electrode redox reactions on the SERS enhancement has been investigated. Finite element electromagnetic modeling has also been developed to simulate the electric field amplitude distribution and the corresponding Raman enhancement factors surrounding arrays of nanopyramids.

SynopsisGlow discharge polymerization among such reactive functional silanes as 3-methacryloxypropyltrimethoxysilane (MSL), 3-glycidoxypropyltrimethoxysilane (ESL), and vinyltrimethoxysilane (VSL) on poly (methyl methacrylate) was investigated by means of Fourier transform infrared spectroscopy, ESCA analysis, and contact angle measurement. Flow rate of monomer influenced both polymer deposition rate and polymer elemental composition. Infrared spectra showed differences in chemical structure among the polymers prepared from the different silanes. All of the polymers obtained contained similar chemical groups such as -CH,, -CH,-, Si-0-Si , and Si-0-C . Polymers deposited from MSL and ESL contained highly hydrophilic functional groups like C-OH, Si-OH, and C=O on the uppermost layer while that from VSL contained highly hydrophobic functional groups like -CH, groups. Chemical analysis by ESCA and contact angle measurement gave evidence for the similarity of the polymers prepared from MSL and ESL, in contrast with the differences of the polymers prepared from VSL.