Biomedical subjects

Jason H Rouse

Publications and source records attributed to Jason H Rouse.

3 recordsLinked to original sources

PubMed2005

Polymer-assisted dispersion of single-walled carbon nanotubes in alcohols and applicability toward carbon nanotube/sol-gel composite formation.

Single-walled carbon nanotubes (SWCNTs) were directly dispersed into various alcohols by sonicating the nanotubes in the presence of poly(4-vinylpyridine) (P4VP). Depending upon the alcohol, it was possible to disperse up to 0.3 g of SWCNTs per liter of alcohol using only 0.6 g of P4VP, and with solution stability greater than 6 weeks. Scanning electron microscopy of "bucky" paper prepared from the polymer-treated nanotubes revealed reduced bundle size compared to the corresponding untreated nanotube paper. Additionally, the applicability of the dispersion system in the formation of SWCNT/silica composites is demonstrated.

Journal Article↗

PubMed2003

Preparation of thin silica films with controlled thickness and tunable refractive index.

Silica films with controlled thickness and refractive index have been formed by the sequential adsorption of a cationic polyelectrolyte and silica sols. The conditions used to prepare the sol were varied, and allowed films with refractive indices as low as 1.16 to be obtained. The sequential adsorption technique allows the thickness of these films to be controlled in increments of 5-10 nm, depending on the desired refractive index. Scanning electron microscopy revealed that a low packing density of constituent silica particles was responsible for the low indices of these films. The as-adsorbed films are thermally robust; calcination at 500 degrees C resulted in only very small decreases in film thickness (by < or =1.8%) and refractive index (to as low as 1.14). After calcination, the silica films remained hydrophilic and sorbed water vapor from the atmosphere. As a result, the refractive indices of these films increased with increasing relative humidity (RH). The dependence of the refractive index on RH was eliminated by treating the calcined films with trimethylchlorosilane.

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PubMedDate not supplied

A method for imaging single clay platelets by scanning electron microscopy.

A method for preparing and observing clay platelets for size and shape analysis using scanning electron microscopy (SEM) was developed. Samples of the clay platelets were prepared by polyelectrolyte-assisted adsorption onto a pyrolytic graphite surface. The use of graphite as a substrate was advantageous because of the low number of secondary electrons emitted from it during imaging by SEM. The resulting low background noise allowed the emission from the approximately 1 nm thick clay sheets to be clearly visualized. Images of centrifuged montmorillonite showed large exfoliated platelets with lateral dimensions between 200 and 600 nm. In contrast, uncentrifuged montmorillonite appeared to contain a large amount of unexfoliated clusters. Although it was not possible to obtain high-quality images of the smaller sheets of Laponite RD, the images of this material did contain size features comparable to the approximately 30 nm2 size reported previously using light scattering, as well as transmission electron and atomic force microscopies.

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