Nanoengineering of a biocompatible organogel by thermal processing.
ABSTRACT The formation of most organogels requires the compatibility of both the gelator and solvent. It is very desirable if the rheological properties of a gel can be manipulated to achieve the desired performance. In this paper, a novel organogel was developed and its rheological properties and fiber network were engineered by controlling the thermal processing conditions. The gel was formed by the gelation of 12-hydroxystearic acid as a gelator in benzyl benzoate. It was observed that the degree of supercooling for gel formation has a significant effect on the rheological properties and fiber network structure. By increasing supercooling, the elasticity of the gel was enhanced, and the correlation length of the fibers was shortened, leading to the formation of denser fiber networks. The good biocompatibility of both the gelator and solvent makes this gel a promising vehicle for a variety of bioapplications such as controlled transdermal drug release and in vivo tissue repair.
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ABSTRACT: Tuning structures: We report a synthetically simple yet structurally rich gelator that self-assembles through hydrogen bonding under different cooling regimes into different nanoscale morphologies (see figure), which can be covalently captured and stabilised by alkene metathesis.Chemistry 06/2009; 15(26):6340-4. · 5.93 Impact Factor
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ABSTRACT: The lengths of the 12-hydroxystearic acid (12HSA) fibers are influenced by crystallographic mismatches resulting from the incorporation of 12HSA monomers into the crystal lattice in an imperfect manner. On a molecular level, this can be differentiated using synchrotron Fourier transform infrared (FTIR) spectroscopy by monitoring the change in area of the 1700 cm(-1) and 3200 cm(-1) peaks, corresponding, respectively, to the dimerization of the carboxylic acid groups and hydroxyl non-covalent interactions, during crystallization. The crystallographic mismatch is attributed to a plateau in the apparent rate constant for the dimerization of the carboxylic acid head groups while the hydroxyl interactions linearly increase as a function of cooling rate (phi). The rate constant for hydroxyl interactions linearly increases as a function of cooling rate while a plateau is observed for the rate of dimerization at cooling rates between 5 and 7 degrees C min(-1). At cooling rates greater than 5 to 7 degrees C min(-1) 12HSA monomers do not effectively dimerize before being incorporated into the crystal lattice causing crystal imperfections impeding linear epitaxial crystal growth and produces branched fibers. At slow cooling rates (i.e., less than 5 to 7 degrees C min(-1)), long fibers are produced with a fractal dimension between 0.95 and 1.05 and for rapid cooling rates (i.e., greater than 5 to 7 degrees C min(-1)) short branched fibers are produced with a fractal dimension between 1.15 and 1.32.Soft Matter 01/2010; 6(2):404-408. · 3.91 Impact Factor
- Advanced Functional Materials 08/2010; 20(19):3196 - 3216. · 9.77 Impact Factor