University researchers have developed methods to synthesize structured glassy carbon nanofibers inside the pores of a porous silicon template by carbonization and obtain free-standing nanofiber by dissolution of the porous silicon template. The carbon nanofibers adopt the shape and morphology of the porous silicon template. The carbon/porous silicon composites are robust, surviving repeated thermal and organic vapor adsorption cycles. The carbon nanocasting approach creates surfaces that: (a) have increased affinity for non-polar organic molecules such as toluene, leading to a 10× improvement in the sensitivity of the sensor; (b) have increased surface area relative to the template leading to greater capacity as an adsorbent; (c) are very stable; and, (d) uniformly cover the underlying silicon layer. (more...)

Presented here is the novel mechanical application of adhesive hydrophobic materials to substrates, the patterning of these materials, and the controlled dip-coating of the resulting patterned substrates to allow the control of the spatial and volumetric attributes of liquid droplets. By controlling the speed with which the substrates are dip-coated, and the viscosity of the polymer bath, fine control over the volumes of liquid that are deposited at particular locations on the substrate is obtained. These techniques may be utilized in a variety of applications including microlens arrays, waveguides, bonding, and fluidic handling. (more...)

Thermoset epoxy primers and coatings are used extensively in a number of industries today. Thermoset resins have the advantage of relatively low coefficient of expansion when compared to thermoplastic coatings. They more closely match the COE of metal, thus the low differential coefficient of expansion between thermosets and metals reduces the mechanical stresses at the interface. This leads to improved durability as mechanical stresses between the coating and metal due to thermal expansion are reduced. Thermoset coatings are, however, quite brittle and must be applied in thin layers. Also, thermosets require a cure process. Thus, thermosets are excellent adhesives but do not provide an ideal coating for many applications. Although thermoplastic resins have certain advantages over thermoset epoxy resins, including being less permeable, being less brittle and requiring no cure step, they exhibit higher levels of thermal expansion that leads to higher levels of mechanical stress between coatings and the underlying metal surface. In practice, due to poor adhesion, thermoplastics have not found wide utility in the coatings industry when used without thermoset primers. (more...)