Fig. 2.

(A) Counterion cloud (white) surrounding a polyelectrolyte chain (green). The coupled dynamics of the chains and their counterion clouds are measured in the fast mode. (B) Cartoon of several dipole–dipole pairings responsible for microgel-like aggregate formation attributed to the slow mode. Each red arrow denotes a dipole formed by an adsorbed counterion on the polymer backbone. $u_0$ is the magnitude of the average attractive energy between two adjacent dipoles in contact, averaged over different favorable orientations. N is the number of segments between two such physical cross-links.