Grafted carbazole-assisted electrodeposition of graphene oxide.

The electrodeposition of graphene oxide (GO) by covalently linked electroactive monomer, carbazole (Cbz) is first demonstrated herein. This is based on the electropolymerization and electrodeposition of covalently linked Cbz units when a potential is applied. During the electrochemical process, the Cbz groups electropolymerize and carry the GO nanosheets as it electrodeposits on the substrate. Moreover, the GO-Cbz sheets selectively deposit onto the conducting regions of the substrate, which demonstrates its promise for the fabrication of electropatterned graphene-based devices. In addition, GO-Cbz is a promising material for the fabrication of nanocomposite coatings for anticorrosion application. In as little as 1 wt % GO-Cbz loading, a protection efficiency as high as 95.4% was achieved.

Colloidally templated two-dimensional conducting polymer arrays and SAMs: binary composition patterning and chemistry.

A facile approach and strategy toward binary-composition, two-dimensional (2D) patterned surfaces of conducting polymer periodic arrays, together with thiol self-assembled monolayers (SAMs) is described. The method involved a Langmuir-Blodgett (LB)-like deposition of latex microsphere particles, electropolymerization via cyclic voltammetric (CV) techniques, and self-assembly of an amphiphile. The LB-like technique enabled the monolayer deposition of different sizes of polystyrene (PS) particles in hexagonal packing arrangement on planar substrates. Combining the LB-like method with CV electropolymerization is advantageous because it provides deposition control of a polymer interconnected network, controlled composition ratio of polymer and SAMs, and control of 2D size and spacing of the spherical void pattern. Electrochemical-quartz crystal microbalance (EC-QCM) in situ monitoring of the film deposition quantified a constant and linear growth rate, with varying viscoelastic behavior of the conducting polymer adsorption on planar and PS-templated substrates. The dual-patterned surface provided a good imaging contrast as observed by atomic force microscopy (AFM). Complementary analyses such as X-ray photoelectron spectroscopy (XPS), attenuated total internal reflection infrared (ATR IR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, and static contact angle measurements were used to characterize the formation of the patterned surface. The versatility of the method enables the potential for making various types of quantitative binary compositions and patterned surfaces using different combinations of conducting polymer or functional SAMs, which can be extended in the future to polymer brushes and layer-by-layer assembly of various materials.

Synthesis and electrografting of dendron anchored OEGylated surfaces and their protein adsorption resistance.

In this study, a series of electrochemically active oligo(ethylene glycol) (OEG) linear-dendrons have been synthesized and grafted onto electrode surfaces by cyclic voltammetry (CV) to improve protein resistance. Dendronized molecules with peripheral carbazole functionality and branching architecture enabled tethering of the poly(ethylene glycol) (PEG) or OEG group with a predictable number of electrochemical reactive groups affecting OEG distribution and orientation. It is possible that ample spacing between the OEG chains affects the intrinsic hydration of these layers and thus surface protein resistance. The films were characterized by CV, surface plasmon resonance (SPR), static contact angle measurements, and atomic force microscopy (AFM). This approach should enable improved nonbiofouling properties on biorelevant electrode surfaces (metal or metal oxides) by potentiostatic or potentiodynamic electrochemical methods, providing an alternative to the self-assembled monolayer (SAM) approach for anchoring PEG layers.