Experimental and Numerical Investigation into the Effect of Water Uptake on the Capacitance of an Organic Coating.

Water uptake by organic coating systems used for corrosion prevention on airframes is one of the principal contributors to the loss of barrier properties of the coating. We used equivalent circuit analyses of electrochemical impedance spectroscopy (EIS) data to track changes in coating layer capacitance for a two-layer coating system consisting of an epoxy primer and polyurethane topcoat immersed in NaCl solutions with different concentrations and temperatures. The capacitance curve exhibited two different response regions, consistent with the "two-stage kinetics" mechanisms for water uptake by the polymers.

Direct Observation of Corrosive Wear by Scanning Probe Microscopy.

Tribocorrosion involves mechanical wear in a corrosive environment, damaging the protective oxide layer of passivating alloys and increasing material loss rates. Here, we develop a nanoscale, technique using scanning probe microscopy in an electrochemical cell to explore the phase-by-phase tribocorrosion behavior of a heat-treated duplex stainless-steel alloy with secondary phases. We found that under anodic potentials well within the passive oxide region, sliding mechanical contact initiated pitting corrosion and increased electrochemical cell current localized to regions undergoing pitting.

A Parameter Study for 3D-Printing Organized Nanofibrous Collagen Scaffolds Using Direct-Write Electrospinning.

Collagen-based scaffolds are gaining more prominence in the field of tissue engineering. However, readily available collagen scaffolds either lack the rigid structure (hydrogels) and/or the organization (biopapers) seen in many organ tissues, such as the cornea and meniscus. Direct-write electrospinning is a promising potential additive manufacturing technique for constructing highly ordered fibrous scaffolds for tissue engineering and foundational studies in cellular behavior, but requires specific process parameters (voltage, relative humidity, solvent) in order to produce organized structures depending on the polymer chosen.