Evingür, Gülşen AkinPekcan, Önder2019-06-272019-06-27201250170-08390170-0839https://hdl.handle.net/20.500.12469/954https://doi.org/10.1007/s00289-011-0625-6Temperature sensitive copolymers were prepared by free radical crosslinking copolymerization in aqueous solution with different molar percentage of N-isopropylacrylamide (NIPA) and acrylamide (AAm) monomers. NN'-methylenebis (acrylamide) (BIS) and ammonium persulfate (APS) were used as a crosslinker and an initiator respectively. The steady-state fluorescence (SSF) technique was used to determine the low critical phase transition temperature (LCST) for PAAm-NIPA copolymers. Swelling experiments were performed in water at various temperatures by real time monitoring of pyranine (Py) fluorescence intensity I which decreased as swelling proceeded. The Stern-Volmer equation is modified for low quenching efficiencies to interpret the behavior of pyranine intensity during the swelling of PAAm-NIPA copolymers. The Li-Tanaka equation was used to determine the swelling time constants tau (1) and the cooperative diffusion coefficients D (0) from fluorescence intensity weight and volume variations of the copolymers at various temperatures. It was observed that tau (1) first increased up to LCST and then decreasednaturally D (0) decreased up to LCST and then increased upon increasing temperature. It was understood that (LCST) increases as PAAm contents increase in the PAAm-NIPA copolymers.eninfo:eu-repo/semantics/openAccessSwellingFluorescenceNIPAPolyacrylamideCopolymerLCSTArticle223238168WOS:00029773870001610.1007/s00289-011-0625-62-s2.0-84856333875N/AN/A