Tunable Protein and Bacterial Cell Adsorption on Colloidally Templated Superhydrophobic Polythiophene Films

A facile approach for enabling or inhibiting the adsorption of protein and adhesion of bacterial cells on a potential-induced reversibly wettable polythiophene film is described. The superhydrophobic polymeric surface was first prepared by a two-step process that combines the layering of polystyrene (PS) latex particles via a Langmuir–Blodgett (LB)-like technique followed by cyclic voltammetric (CV)–electrodeposition of polythiophene from a terthiophene ester monomer. The polythiophene conducting polymer coating enabled control of the wettability of the surface by simply changing its redox property via potential switching. The influence of morphology on this switching behavior is also described. The wettability in return controls the adsorption of protein and adhesion of bacterial cells. For instance, the undoped polythiophene film, which is superhydrophobic, inhibits the adhesion of fibrinogen proteins and Escherichia coli (E. coli) cells. On the other hand, the doped film, which is hydrophilic, leads to increased attachment of both protein and bacteria. Unlike most synthetic antiwetting surfaces, the as-prepared superhydrophobic coating is nonfluorinated. It maintains its superhydrophobic property at a wide range of pH (pH 1–13) and temperature (below ?10 °C and between 4 and 80 °C). Moreover, the surface demonstrated self-cleaning properties at a sliding angle as low as 3° ± 1. The proposed methodology and material should find application in the preparation of smart or tunable biomaterial surfaces that can be either resistant or susceptible to proteins and bacterial cell adhesion by a simple potential switching

Superhydrophobic Colloidally Textured Polythiophene Film as Superior Anticorrosion Coating

In this paper, we demonstrated for the first time the use of electrodeposited superhydrophobic conducting polythiophene coating to effectively protect the underlying steel substrate from corrosion attack: by first preventing water from being absorbed onto the coating, thus preventing the corrosive chemicals and corrosion products from diffusing through the coating, and second by causing an anodic shift in the corrosion potential as it galvanically couples to the metal substrate. Standard electrochemical measurements revealed the steel coated with antiwetting nanostructured polythiophene film, which was immersed in chloride solution of different pH and temperature for up to 7 days, is very well protected from corrosion evidenced by protection efficiency of greater than 95%. Fabrication of the dual properties superhydrophobic anticorrosion nanostructured conducting polymer coating follows a two-step coating procedure that is very simple and can be used to coat any metallic surface

Tunable Protein and Bacterial Cell Adsorption on Colloidally Templated Superhydrophobic Polythiophene Films

A facile approach for enabling <i>or</i> inhibiting the adsorption of protein and adhesion of bacterial cells on a potential-induced reversibly wettable polythiophene film is described. The superhydrophobic polymeric surface was first prepared by a two-step process that combines the layering of polystyrene (PS) latex particles via a Langmuir–Blodgett (LB)-<i>like</i> technique followed by cyclic voltammetric (CV)–electrodeposition of polythiophene from a terthiophene ester monomer. The polythiophene conducting polymer coating enabled control of the wettability of the surface by simply changing its redox property via potential switching. The influence of morphology on this switching behavior is also described. The wettability in return controls the adsorption of protein and adhesion of bacterial cells. For instance, the undoped polythiophene film, which is superhydrophobic, inhibits the adhesion of fibrinogen proteins and <i>Escherichia coli</i> (<i>E. coli</i>) cells. On the other hand, the doped film, which is hydrophilic, leads to increased attachment of both protein and bacteria. Unlike most synthetic antiwetting surfaces, the as-prepared superhydrophobic coating is nonfluorinated. It maintains its superhydrophobic property at a wide range of pH (pH 1–13) and temperature (below −10 °C and between 4 and 80 °C). Moreover, the surface demonstrated self-cleaning properties at a sliding angle as low as 3° ± 1. The proposed methodology and material should find application in the preparation of smart or tunable biomaterial surfaces that can be either resistant or susceptible to proteins and bacterial cell adhesion by a simple potential switching

Freestanding Macroporous Silicon and Pyrolyzed Polyacrylonitrile As a Composite Anode for Lithium Ion Batteries

Silicon continues to draw great interest as an anode material for lithium ion batteries due to its large specific capacity for lithium. Macroporous silicon produced by electrochemical etching is one of several anode materials of interest, but its energy density is oftentimes limited due to its attachment to an unreactive silicon substrate. Here, we present a novel “lift-off” method by which a freestanding macroporous silicon film (MPSF) is electrochemically detached from the underlying bulk silicon and combined with pyrolyzed polyacrylonitrile (PAN), a conductive polymer that forms a conjugated-chain chemical structure. We report the performance of these silicon thin films with and without pyrolyzed PAN