Non-self-similar aggregation of methylcellulose

Aggregation of methylcellulose in aqueous dilute solution is studied by light and small angle neutron scattering. For temperature T<293.15K, the free chains adopt a swollen conformation. For T>313.15K, a slow aggregation kinetics occurs. At qR_g<1, the association number is found to vary as R_g³. However at qR_g>1, the scattered intensity decreases as q^{−(1<d≤1.3)} depending on the temperature. At even higher q, one observes a local compaction as aggregation proceeds, as revealed by a more and more pronounced Porod's behaviour. Results are discussed in terms of non self-similar growing aggregates, having neither a rod-like nor a dense structure.