Ageing of fluorescent and smart naphthalene labeled poly(acrylic acid)/cationic surfactant complex

Abstract

The self-development of associates between naphthalene labeled poly(acrylic acid) (PAA25Np42) and dodecyltrimethylammonium chloride (C12TAC) was studied using measurements of surface tension, pH, turbidity, electrophoretic mobility, dynamic light scattering and fluorescence. A peculiar surface tension behavior was revealed in the adsorption process of polymer/surfactant (PS) complex at air/water interface. The turbidity and electrophoretic mobility monitored the stable and unstable colloidal PS complexes in acidic microenvironment. The polymer self-aggregation and surfactant-polymer association were assessed by fluorescence during two weeks. The naphthalene monomer sensed the time-stability of PS complex at low and high surfactant-to-polymer ratios. The time-induced phase separation region of PS complex was emissively identified. The unfolding of aged polymer coil and the higher tendency for the cooperative binding of surfactant onto the macromolecular chain were unveiled. The study is useful to implementing efficient and synergetic formulations of nanomaterials for medical and environmental applications.