Controlling polymer conformations at particulate interfaces

Polymers can be localized at surfaces through covalent bonds or thermodynamic attractions. The surface then modifies the conformation of polymers through two primary mechanisms. First, the surface tether prevents spatial fluctuations of the attached monomers, and second, the surface localization of the chains increases the local monomer concentration. These conformational changes suggest that the thermodynamics of these surface-localized chains are significantly altered from those of free linear chains. Here, we discuss how we can modify these thermodynamics in two stories. First, we use telechelic triblock copolymers to bridge between emulsion droplets. By adding these endblock associating polymers to a suspension of oil droplets, we link them into a cohesive elastic network, the elasticity of which is governed by the propensity of these polymers to adopt bridging conformations. We modify the conformation of the midblock to promote bridging and drive the system to a more elastic state. Second, we discuss how surfaces alter the phase behavior of polymer solutions. By grafting polymers to particulate surfaces, we suppress the Θ-temperature in lower critical solution temperature (LCST) systems. We continue to explore this effect with diblock copolymers localized at emulsion interfaces to assess the role of surface motility on these suppressed thermodynamics.