Synthesis, characterisation and self assembly of biosurfactants based on hydrophobically-modified inulins

Kokubun, S, Ratcliffe, Ian and Williams, Peter A (2013) Synthesis, characterisation and self assembly of biosurfactants based on hydrophobically-modified inulins. Biomacromolecules, 14 (8). pp. 2830-2836. ISSN 1525-7797

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Novel biosurfactants have been synthesised using a low energy, environmentally friendly process by the derivatisation of inulin with octenyl (OSA) and dodecenyl (DDSA) succinic anhydrides in aqueous solution. The inulin and its derivatives have been characterised using GPC/MALLS, HPAEC-PAD, FTIR and NMR and the reaction efficiency was found to be between 59-95 %. The efficiency was generally higher for OSA derivatives compared to DDSA derivatives. The hydrophobic derivatives were found to aggregate in solution and the critical aggregation concentration (CAC) was determined using dye solubilisation, surface tension, dynamic light scattering and conductivity. There was reasonable agreement in the CAC values obtained by the different techniques except for conductivity. It was found that the CAC decreased with increasing alkenyl chain length and degree of modification and the values were significantly lower for the DDSA derivatives compared to the OSA derivatives. GPC elution profiles for the DDSA-inulin using 12 mole % reagent confirmed the presence of aggregates with a molecular mass of ~2.5 x 106 g/mol and a radius of gyration of ~25 nm corresponding to ~550 inulin molecules. Dynamic light scattering (DLS) study was undertaken to determine the hydrodynamic radius and values obtained for the DDSA (12 %) derivative were 30 nm in both water and 0.1 M sodium nitrate, while for the OSA (12 %) derivative values of 13 nm and 7 nm were obtained. The derivatives have potential application in the stabilisation of particulate dispersions and emulsions and also in the encapsulation and delivery of drugs.

Item Type: Article
Keywords: Inulin, critical aggregation concentration, alkenyl succinic anhydrides, dye solubilisation, dynamic light scattering, surface tension
Divisions: Applied Science, Computing and Engineering
Depositing User: Mr Stewart Milne
Date Deposited: 23 Feb 2015 15:17
Last Modified: 19 Dec 2017 15:28

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