Interaction between pentaethylene glycol n-octyl ether and low-molecular-weight poly(acrylic acid)

Interaction between pentaethylene glycol n-octyl ether and poly(acrylic acid): Effect of the polymer molecular weight

“…Only a very slight slope change at T 1 = 3.3 × 10 −3 mol kg −1 is detectable, above which surface tension continues to decrease, , from Ref. [18]. w P = 0.1% w/w in both cases.…”

“…In contrast, the ternary system water-C 8 E 5 -PAA ( M w = 2000) presents a quite different γ trend [18], see Fig. 1.…”

“…1 on a semilogarithmic scale. With increasing m, the surface tension, γ , decreases; as the critical micellar concentration (cmc = 7.0 × 10 −3 mol kg −1 ) is reached, the curve changes its slope and approaches to a constant value, γ cmc = 31.3 mN m −1 [18].…”

“…Binary mixtures water-C 8 E 5 , from Ref. [18]. Table 1 Critical surfactant concentrations a in the ternary systems water-C 8 E 5 -PAA (0.1% w/w) at various polymer molecular weight, as evaluated by tensiometry even if with a lower slope.…”

“…In a previous paper [18], we reported and discussed the results of an experimental investigation on the aqueous mixtures of the ethoxylated surfactant pentaethylene glycol n-octyl ether (C 8 E 5 ) with a low-molecular-weight poly(acrylic acid) sample (PAA, average molecular weight 2000). We found that C 8 E 5 interacts with low-molecular-weight PAA, leading to the formation of surfactant clusters bound to the polymer chain at a surfactant molality (T 1 ) lower than the critical micelle concentration (cmc) of C 8 E 5 .…”