| 1. |
- Khan, A., et al.
(författare)
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Holographic recording in cross-linked polymeric matrices through photoacid generation
- 2008
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 20:11, s. 3669-3674
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Tidskriftsartikel (refereegranskat)abstract
- We report a novel strategy for writing volume holograms by photoacid generation and subsequent acid-catalyzed degradation leading to increased free volume/refractive index modulation in the exposed regions of a cross-linked rigid polymeric matrix. This strategy offers nondestructive read out and high diffraction efficiency and allows optical-quality, millimeter thick films to be fabricated that possess excellent thermal and dimensional stability. A key feature of this approach is the efficient acid-catalyzed degradation of functional groups in the cross-linked matrix leading to release of volatile products which diffuse readily out of the thick films. Furthermore, the reported data storage material is lightweight and inexpensive and can be easily processed into different shapes, making it an attractive candidate for data storage applications.
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| 2. |
- Muhammed, Mamoun, et al.
(författare)
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Nanostructured Skutterudites
- 2006
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Ingår i: Thermoelectrics Handbook. - : Taylor & Francis Group. - 0849322642 ; , s. 41-1-41-10
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Bokkapitel (refereegranskat)
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| 3. |
- Toprak, Muhammet S., 1973-, et al.
(författare)
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Control of size and permeability of nanocomposite microspheres
- 2007
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 19:17, s. 4263-4269
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Tidskriftsartikel (refereegranskat)abstract
- This work reports on progress in controlling the size and porosity of spontaneously assembled composite polyelectrolyte microspheres for their potential use in targeted drug delivery applications. In this study, the composite polyelectrolyte microsphere is exemplified by PLK/TSC containing magnetic nanoparticles. The stability of these microspheres against environmental alterations such as pH, ionic strength, and dilution is a critical issue for practical considerations. The effects of ionic strength and dilution on the size of these hybrid spheres were investigated by the addition of salts with different cationic charges and deionized water. Increasing both ionic strength and dilution caused a decrease in the average size of microspheres from similar to 700 to similar to 200 nm. Ions of +2 charge were observed to screen interactions between the assembling components via a substitution effect. The composite polyelectrolyte microspheres could be mechanically stabilized by cross-linking with glutaraldehyde (GA). The microsphere permeabilities were analyzed using fluorescein-tagged dextran molecules of different MW with confocal laser scanning microscopy and fluorescence recovery after photobleaching. Microsphere permeabilities and critical pore sizes could be controllably decreased by altering the extent of cross-linking, which was monitored by UV-vis spectroscopy. Quantitative analysis revealed that cross-linking can be used to control the diffusion coefficient of dextran and can reduce it by 4 orders of magnitude.
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| 4. |
- Toprak, Muhammet, 1973-, et al.
(författare)
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Tailoring magnetic microspheres with controlled porosity
- 2007
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Ingår i: Heterogeneous Integration of Materials for Passive Components and Smart Systems. - : Materials Research Society. - 9781558999268 ; , s. 93-98
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Konferensbidrag (refereegranskat)abstract
- The synthesis of organic and inorganic nano- and microspheres has attracted much interest for a variety of applications ranging from drug delivery to chemical storage and catalysis. We recently demonstrated the assembly of magnetic nanoparticles and polycations into hybrid microspheres in a single-step synthesis via complex coacervation. These microspheres showed viability for bio-applications as indicated by toxicity tests, and are therefore potential targeted drug delivery devices, as they can be directed magnetically. This work reports the recent progress on the potential use of these assemblies in drug release by controlling their porosity. Fluorescein tagged dextran molecules with different MW have been infiltrated into these entities to determine critical pore size by confocal fluorescence microscopy. Different physicochemical characterization results are also presented.
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