Study on self-assembly properties of thermosensitive fluorinated hydrophobically associating polyacrylamide

Abstract

This paper describes the preparation of a novel thermosensitive fluorinated surface-active monomer (TFSM) that is based on isophorone diisocyanate(IPDI), dodecafluoroheptanol (FOH), and allyl polyethylene glycol (APEG) with different molecular weights, which is used to prepare thermosensitive fluorinated associating polyacrylamide (TFHPAM) with a functional monomer 2-acrylic amide-2 methyl propyl sulfonic acid (AMPS) through a new micellar system. The thermosensitive self-assembly properties of TFHPAM are studied by viscosimetry, rheology, and dynamic light scattering. The results show that, in room temperature, the self-assembly effects of TFHPAM weakens, and the critical associating concentration (CAC) is increased with the increase in length of polyether side chains in APEG. At the higher temperature, the self-assembly performances of TFHPAM will be enhanced, but CAC is decreased with the increase in length of polyether side chains. Also, the CAC of TFHPAM is decreased along with the increasing temperature. The self-assembly behaviors of TFHPAM via increasing temperature in dilute and semidilute solutions are totally different. At different temperatures, the effects of shear rate on the apparent viscosity of the TFHPAM (via different length of polyether side chains in APEG) solutions are also different. The average apparent aggregate size is increased and the distribution of apparent aggregate size changes from monodispersion to polydispersion, to some extens, with the increase of temperature .