Phase separation of aqueous solution of methylcellulose

摘要: As we determined visually by the temperature cloud point method, coexistence phase curve of methylcellulose in aqueous solution belongs to LCST (low critical temperature) type. Rheological dynamic measurements reveal existence three gel domains. The (I) localized homogeneous at low concentration and temperature, is a very weak gel, where cross-links are attributed pairwise hydrophobic interactions between most zones backbone: trimethyl blocks. second (II) was revealed high regime below LCST, it may be formation crystallites which play role cross-linking points. third concomitant micro-phase separation. In these turbid gels, syneresis develops slowly with time: higher lower concentration, faster syneresis. Near sol-gel transitions, power law frequency dependence loss storage moduli observed viscoelastic exponent Δ(G′ G″ ω Δ) found 0.76 0.8 reach 1 concentration.