Thermoresponsive self-assembly of amphiphilic poly(N-vinylcaprolactam)-b-poly(vinyl chloride) diblock copolymers: From controlled synthesis to stable nanoparticles

A series of well-defined amphiphilic poly( N -vinylcaprolactam)- b -poly(vinyl chloride) (PNVCL- b -PVC) diblock copolymers with different block contents was successfully synthesized by macromolecular design via the interchange of xanthates (MADIX) polymerization. The compositions and molecular weight distributions of the copolymers were determined by 1 H nuclear magnetic resonance spectroscopy ( 1 H NMR) and size exclusion chromatography (SEC) respectively. The self-assembly and thermoresponsive behavior of PNVCL n - b -PVC m in water and water/DMF (50/50 % v /v) is reported for the first time. The thermoresponsivity of the self-assembled structures was investigated using dynamic light scattering (DLS) and transmittance. The performance of the self-assembly was evaluated depending on the design of the copolymers (composition and molecular weight) and the conditions of the medium (concentration and solvent). The resulting nanostructures were identified and characterized by transmission electron microscopy (TEM), and atomic force microscope (AFM) analysis confirmed the spherical aggregate structure of the particles. The precise internal structure of the micelles was analyzed by small-angle X-ray scattering (SAXS) and a core-shell model. The ability of PNVCL- b -PVC copolymers to self-assemble and form small, stable nanoparticles makes them a promising material for future applications, especially for coatings and lithography. This work sets a precedent for further studies on self-assembly with PVC and other related block polymers. • PNVCL- b -PVC block copolymers were synthesized using MADIX polymerization. • Thermoresponsive self-assembly behavior of PNVCL- b -PVC copolymers in water and water/DMF mixtures. • Thermoresponsive behavior showed reversible size changes with temperature. • DLS, TEM, AFM, and SAXS confirmed the micellar core-shell structures.