Threading, Growth, and Aggregation of Pseudopolyrotaxanes

Abstract

The formation of supramolecular inclusion compounds (pseudopolyrotaxanes) produced by cyclodextrins and polymers can be monitored through turbidimetry. In this paper, we studied the kinetics of the threading of linear poly(ethylene glycol) chains of different molecular weights and of a four-arm star-like polymer as a function of temperature. The main thermodynamic parameters are extracted. The aggregation and precipitation of pseudopolyrotaxanes are described in terms of the Avrami-Erofe'ev model, which provides relevant information on the mechanism of these processes. SAXS and TGA experiments confirm the structure and hydration of the final products obtained from the different polymers. A new hypothesis for the interaction between pseudopolyrotaxanes that leads to aggregation and precipitation, based on the spatial dielectric anisotropy, is proposed.

Structure and rheology of gel nanostructures from a vitamin C-based surfactant

“…Finally, Q = 0 or 1 means no nucleation, or constant nucleation. 17,18 Fig . S1 in the ESI, † shows the results of the linear leastsquares fitting of the plot ln[1 À ln(1 À x(t))] versus ln(t) that gives the kinetic parameters k (from the intercept) and M (from the slope).…”

Fragmentation of molecule-induced γ-cyclodextrin nanotubular suprastructures due to drug dosage

“…Among the cyclodextrins, a-and c-form spherical aggregates, whereas b-forms fiber-like assemblies [12]. Since this phenomenon is more pronounced in case of b-CDs, which affects its solubility in water, more studies have been done over that aspect [13][14][15]. Guest induced nanotubular suprastructures in the cases of a-and c-CDs form elongated rod-like structures.…”

Inclusion complexes synthesized from an ABA triblock polymer and β-cyclodextrins: amplification of hydrophobic interaction along a hydrophilic polymer chain

“…14 As shown in Fig. 1, solution transmittance plots of b-CD, CP1113 and their corresponding IC from the initial state were recorded at 600 nm with a temperature falling rate of 15 C min À1 .…”