Direct observation of dynamic interaction between a functional group in a single SBR chain and an inorganic matter surface.

As a composite of hybrid organic-inorganic materials, blending hydrophilic silica microparticles with oil-extended rubber can improve vehicle tire performance but the nanometer scale effects of microparticle inclusion have not been thoroughly studied. Here, we used atomic force microscopy (AFM) video imaging to closely investigate the behavior of functionalized and unmodified styrene-butadiene rubber (SBR), as models for tire rubber, on mica surfaces. The hydrophilic silica microparticle surface could be simulated by a mica substrate because both have silanol groups on their surface. Using AFM video imaging, we tracked the behavior of individual SBR polymer chains on mica surfaces to reveal how polymer modification affects the interaction of SBR with mica surfaces. We measured the diffusion coefficients and spring constants of single SBR polymer chains for the first time, demonstrating that it is possible to parameterize the relationship between the molecular dynamic structure of a polymer and rubber properties of the vulcanized compound.