Glassy dynamics of model colloidal polymers: Effect of controlled chain stiffness*

Abstract

Colloidal polymers with tunable chain stiffness have been successfully assembled in experiments recently. Similar to molecular polymers, chain stiffness is an important feature which can distinctly affect the dynamical behaviors of colloidal polymers. Hence, we model colloidal polymers with controlled chain stiffness and study the effect of chain stiffness on glassy behaviors. For stiff chains, there are long-ranged periodic intrachain correlations besides two incompatible local length scales, i.e., monomer size and bond length. The mean square displacement of monomers exhibits sub-diffusion at intermediate time/length scale and the sub-diffusive exponent increases with chain stiffness. The data of localization length of stiff polymers versus rescaled volume fraction for different monomer sizes can gather close to an exponential curve and decay slower than those of flexible polymers. The increase of chain stiffness linearly increases the activation energy of the colloidal-polymer system and thus makes the colloidal polymers vitrify at lower volume fraction. Static and dynamic equivalences between stiff colloidal polymers of different monomer sizes have been checked.