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The purpose of the work described here was to prepare covalently crosslinked nanogel from polyethylene glycol diacrylate (PEGDA) using an inverse micelle system as a template for irradiation via electron beam. Inverse micelles were formed by addition of sodium dioctyl sulfosuccinate (AOT) in n-heptane above its critical micelle concentration. These nano sized micelles were used to trap PEGDA in its water phase. Irradiation of the PEGDA containing micelles leads to formation of many radicals and recombinations thus forming crosslinked nanogel.

Micro sized gels have been widely used as drug carriers for its compatibility in blood. Among its important properties are round small dimensions and large surface area. These properties allow for better attachment of ligand and higher stability in the blood stream. In this study,microgels from polyethylene glycol diacrylate (PEGDA) were prepared from its microemulsions form using electron beam with energy of 3 MeVat different irradiation dose of 0 to 25 kGy. Dynamic light scattering (DLS) study revealed that gel with diameter of 70-100 nm with a narrow size distribution was obtained at 5 kGy and 400-550 nm with a broad size distribution at 25 kGy. The molecular weight obtained from GPC-MALLS for the minimum practical dose irradiated has resulted to more than 4.22 x 105 g/mol as compared to7.75 x 102 g/mol forunirradiated polymer. The increase of size and its distribution as well as its molecular weight over the elevation dose were suspected to be due to diffusion of micelles that leads to recombination of macro radicals from different micelles during longer irradiation period at higher doses. Overall findings from this study have proven that PEGDA microgels can be prepared via electron beam radiation with emulsions as templates for polymerization.

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