Kinetically Driven Intra- and Interchain Association of Hydrophobically and Hydrophilically Modified Poly(acrylic acid) in Dilute Aqueous Solutions

Effects of pH dodecyl and PEO contents as well as the method of preparing the solution on the formation of the unimolecular micelles (unimer micelle) or aggregates made of poly(acrylic acid) graft poly(ethylene oxide) graft dodecyl (PAA g PEO g dodecyl) and PAA g dodecyl have been studied by a combination of static and dynamic laser light scattering (SLS and DLS) It revealed that in most cases these copolymers tend to form interchain associates, while low pH value, proper high dodecyl content and fast switch rate of solvent quality promote intrachain association These phenomena of the system being trapped in a metastable state can be mainly attributed to its kinetic pathway the factors mentioned earlier can enhance the initial intrachain contraction leading to tau(c) (interaction time) << tau(e) (entanglement time) for the two interaction intrachain globules So they behave like tiny elastic balls and their further merge/fusion become nearly impossible during their interaction time (tau(c)) In this way the copolymer system is trapped in the metastable, unimer micelle state The interplay of tau(c) and tau(e) in the formation of metastable unimer micelles or stable aggregates has been discussed in detail