Synthesis of 2-{5-[4-((4-nitrophenyl)diazenyl)phenyl]-1,3,4-oxadiazol-2-ylthio}ethyl acrylate monomer and its application in a dual pH and temperature responsive soluble polymeric sensor

The monomer 2-{5-[4-((4-nitrophenyl)diazenyl)phenyl]-1,3,4-oxadiazol-2-ylthio}ethyl acrylate (NDPOE-acrylate) was synthesized in five steps and then copolymerized with N-isopropylacrylamide, leading to a dual pH and temperature responsive polymeric sensor. Obtained copolymer exhibited the lower critical solution temperature only in acidic medium (pH 2) as 32 °C. The UV–vis and fluorescence of copolymer was investigated at different pH values in various temperatures. The UV–vis of copolymer are independent to temperature above pH 4. The copolymer exhibited sensitive fluorescence change towards pH between 2 and 10 at different temperatures.