Influence of anionic surfactant on the rheological properties of hydrophobically modified polyethylene-oxide/cyclodextrin inclusion complexes

Manipulation of hydrophobic interactions in associative polymers using cyclodextrin and enzyme

“…The figure shows that the dynamic moduli decrease on addition of CD and the most reduction is achieved at around 25 moles of CD/mole of macromonomer. The figure also shows that at any CD concentration, the extent of reduction is same at all the frequencies, thus confirming eqn (28),i.e., the ratios G 0 CD /G 0 0 and G 00 CD /G'' 0 are approximately equal at all frequencies. This behavior can be explained as follows.…”

“…19,23,24 The encapsulation of hydrophobic groups by CD reduces the viscosity and other rheological properties of the solution by several orders of magnitude. [16][17][18][25][26][27][28] Although the reduction in the viscosity improves the processability of polymer solutions, it is often necessary to restore the original rheological properties for the intended use of the polymer solution. One of the methods to recover the rheological properties is to add a surfactant that has a higher affinity for CD than the hydrophobes.…”

Studying the interaction of hydrophobically modified ethoxylated urethane (HEUR) polymers with sodium dodecylsulfate (SDS) in concentrated polymer solutions

“…Below C * and analogous to the concentrated regime, the length scales extracted from the polymer scattering contrast (Table S. As an aside, the importance of the urethane linkers in promoting the association of the polymer has been studied by SANS. The ability of β-cyclodextrin to form complexes with the HEUR hydrophobic end-groups has been previously reported by Liao et al (37,38). Here, β-cyclodextrin was added to the polymer solution to form a 1:1 end-group -β-cyclodextrin complex at 5 wt% C6-L-(EO100-L)9-C6 and the scattering from the polymer recorded, and contrasted with the same in the absence of the β-cyclodextrin.…”

A Critical Approach to the Thermodynamic Characterization of Inclusion Complexes: Multiple-Temperature Isothermal Titration Calorimetric Studies of Native Cyclodextrins with Sodium Dodecyl Sulfate

“…A thorough review of thermodynamic data for the CD:SDS complex formation has been performed (Tables and ), − paying special attention to the binding constants. It should be emphasized the lack of temperature-dependent surveys, as well as the fact that almost all of the available quantities refer to the standard temperature 298 K. As illustrated by Table (in section 4.1), the magnitude and even the sign of the thermodynamic parameters may vary with temperature, due to the large heat capacities usually involved in the CD-inclusion complex formation .…”

“…Such a premise is forced in many cases by the low sensitivity of the employed experimental technique. When K 11 and K ij are the same order of magnitude, such inconvenience can be overcome by furnishing the overall binding constant β ij = K 11 K ij , instead of trying to determine the stepwise binding constants separately (see Table ). ,,, Moreover, Pistolis and Malliaris , showed that differentiation between 1:1 and 2:1 stoichiometries by means of computer fitting methods or double-reciprocal plot techniques is not always possible, in which case it is imperative that direct methods be employed to determine the stoichiometry unambiguously. Yet the experimental (or methodological) sensitivity is not the only to blame: As pointed out by Wilson and Verrall, it is also possible to overlook additional complexation equilibria when operating in a limited range of concentration ratios, particularly when K 11 and K ij vastly differ in magnitude.…”