Phase behavior of solvent-rich compositions of the polymer/drug system poly(butylene succinate) and N,N-diethyl-3-methylbenzamide (DEET)

Abstract Poly(butylene succinate) (PBS) is used to produce micro-/nanoporous biodegradable scaffolds, suitable for the release of mosquito repellent N , -diethyl-3-methylbenzamide (DEET), based on thermally induced phase separation. For solvent-rich compositions up 30 m% PBS, it was found that PBS dissolves in DEET at elevated temperatures. During cooling, spherulitic crystallization occurs, with temperature decreasing content and cooling rate, as determined by cloud-point measurements, differential scanning calorimetry, polarized-light optical microscopy. Scaffold morphologies quenched solutions were analyzed electron microscopy a function polymer concentration quenching temperature. These two parameters control nucleus density/spherulite size, degree intermeshing spherulites, intra- interspherulitic pore latter typically being order magnitude few micrometers.