Effect of connectivity on the structure and the liquid-solid transition of dense suspensions of soft colloids

Aqueous solutions of multiarm flower-like poly(ethylene oxide) (PEO) were formed and connected to various degrees by self-assembly. The structure was rendered permanent by in situ UV-irradiation. Dense suspensions of these single and connected soft colloids were studied by static and dynamic light scattering and viscosity measurements. The concentration dependence of the osmotic compressibility, the dynamic correlation length, and the viscosity of single flowers was shown to be close to that of equivalent PEO star-like polymers demonstrating that the effect of forming loops on the interaction is small. It was found that the osmotic compressibility and the dynamic correlation length of dense suspensions are not influenced by the bridging. However, when flower polymers are connected into clusters, motion in dense suspensions needs to be collective over larger length scales. This causes a much stronger increase of the viscosity for dense suspensions of interpenetrated clusters compared to single-flower polymers. © 2015 American Chemical Society.