Preparation of poly (methyl methacrylate) stretched chains by dropping method with dilute solutions and their conformation transition

PMMA stretched chains was prepared successfully by dropping dilute PS-b-PMMA toluene solution, and the morphology and the conformation transition of PMMA stretched chains under acetone and water vapour annealing were characterized by using AFM. The results showed the PMMA stretched chains with height of 0.2 nm and length of 100 nm ∼ 300 nm can be formed on the mica substrate by dropping dilute PS-b-PMMA toluene solution with concentration of 1 × 10^-6; this method can be used for PS-b-PMMA materials with different molecular weights, the highly stretched PMMA chains can be prepared easily when the molecular weight of PMMA segment was larger than that of PS segment. The PMMA stretched chains will be contracted rapidly and fused with PS core to form spherical structure when the surface micelles were annealed by acetone vapour; the conformation transition depended on the initial concentration of preparing surface micelles during annealing with water vapour, the surface micelles prepared by dilute solution of 1 × 10^-6 can be changed into spherical structure only; the micelles having much more PMMA stretched chains prepared with a concentration of 5 × 10^-6 can be assembled into flower like micelles and rod micelles with step-like PMMA molecular layers.