Sharma S.K.,New York UniversityAbu Dhabi |
Jagannathan R.,New York UniversityAbu Dhabi
Journal of Supercritical Fluids | Year: 2016
We report the results of our research on the RESS precipitation of molecular clusters of ibuprofen with four different surfactants and the effect of surfactant concentration on their size. Our custom designed, liquid N2 cooled collection process of the molecular clusters embedded in "dry ice", resulted in yields of up to 80% (w/w). Sublimation of the 'dry ice' in deionized water resulted in dispersions of ibuprofen in water. These dispersions were found to be stable at room temperature, for up to six months, as confirmed by DLS and AFM characterizations. Solution casting of the dispersions on silicon and sapphire substrates resulted in high quality, "liquid like" viscous films as observed by optical microscopy and AFM. XRD and confocal Raman characterizations confirmed that the molecular clusters retained their chemical identity of ibuprofen. Besides its scientific importance, this invention is expected to open up new drug delivery platforms. © 2015 Elsevier B.V.
Rianasari I.,New York UniversityAbu Dhabi |
Weston J.,New York UniversityAbu Dhabi |
Rowshan R.,New York UniversityAbu Dhabi |
Blanton T.,International Center for Diffraction Data12 Campus BoulevardNewtown Square |
And 2 more authors.
Journal of Applied Polymer Science | Year: 2014
We report the formation of cohesive, mechanically robust thin films of Teflon-AF formed via self-assembly of nanoparticles at both air/water and oil/water interfaces of micro-emulsion droplets. We also present results of morphological and mechanical investigations of thin films formed at these oil/water interfaces. Scanning electron microscope and low angle X-ray diffraction characterization of drop cast thin films from the micro-emulsions showed the presence of stacks of nanosheets with an average thickness of 6 nm. Atomic force microscopy (AFM) characterization put the thickness at a much lower value of around 2 nm implying that these sheets are comprised of molecular sheets of Teflon-AF. AFM characterization also indicated that these sheets are stretched molecular films comprising inter-diffused molecular chains, arranged in a regular fashion. Nanoindentation studies of these films unambiguously demonstrated the "tablet sliding" mechanism, similar to nacre, for dissipating applied stress. © 2014 Wiley Periodicals, Inc.