Copolymer Self Research Articles

Diffusion Processes of Interacting Brownian Particles in Blockcopolymer‐Microemulsion Transient Networks

AbstractQuasielastic light‐scattering and pulsed field gradient NMR were used to investigate the effects of a triblock copolymer and a α‐ω telechelic ionomer on the interaction potential and transient network formation of nanodroplets in w/o microemulsions. The NMR self diffusion measurements yield a crossover from restricted polymer diffusion to free self diffusion. The relation between the copolymer self diffusion and the dynamic properties of the transient network are explained in the framework of reversibly cross linked polymer chains. Quasi‐elastic light‐scattering, only sensitive to the correlations between the waterdroplets, yields three diffusive processes, which are due to fast collective diffusion and slowly decaying correlations, controlled by the specific interactions of the hydrophilic and hydrophobic blocks with the water and oil phases.

Morphologies in Blends of Diblock Copolymer and Homopolymer: Morphology Diagrams and the Intermaterial Dividing Surface

AbstractBinary blends of diblock copolymer (AB) and homopolymer (hA) self assemble upon solvent evaporation into a great variety of microphase separated morphologies. The ordered lamellar, bicontinuous double diamond, cylindrical and spherical morphologies were observed by TEM and SAXS in our studies, as well as a range of micellar morphologies.The mean curvature (H) and the area per copolymer junction (σj), which characterize the intermaterial dividing surface, increased with increasing homopolymer concentration in the blend and/or with decreasing homopolymer molecular weight. These trends were generally obeyed both between and within ordered morphology types. The increase in H and σjwas related to an increased degree of mixing between the homopolymer and the block of the copolymer.Two types of isothermal morphology diagrams were constructed to consolidate the extensive morphological data and to illustrate the general morphological transitions in AB/hA blends. The constant molecular weight morphology diagrams illustrated the interdependence of the copolymer composition and the homopolymer concentration. The constant copolymer composition diagrams emphasized the importance of the relative homopolymer molecular weight and the overall blend composition.