Associative networks of cholesterol-modified dextran with short and long micelles

Abstract

The strong associative behaviour between cholesterol-modified dextran (CMD) and short and long polyoxyethylene cholesteryl ether (ChEO 10 ) micelles were investigated using rheology and small-angle neutron scattering (SANS). In solutions of short rod-like micelles (ChEO 10 alone), the addition of 5.0 wt% CMD induced a remarkable transition from a Newtonian system to a highly solid-like viscoelastic network, with an increase in zero-shear viscosity of over 5 orders of magnitude. The frequency sweeps at ChEO 10 concentrations above 2.5 wt% were fitted to a Maxwell model with 3 elements and, quite remarkably, fell onto a single master curve, while no network was formed at 2.5 wt% micelles. Viscoelastic solutions of wormlike micelles (WLMs) were obtained by adding the co-surfactant triethylene glycol monododecyl ether (C 12 EO 3 ) to ChEO 10 solutions at a constant ChEO 10 /C 12 EO 3 ratio of 5/1. The introduction of CMD into the WLM solutions induced a transition to a more liquidlike behaviour (G 00 /G 0 increased), however both moduli increased by one order of magnitude. At the lowest ChEO 10 concentration (2.5%), the solid-like behaviour was lost. Overall, a comparable rheological response was obtained for the WLM and the short rods with CMD, however the WLM/ CMD behaviour suggested a wider spectrum of relaxation processes, longer relaxation times and higher plateau moduli. SANS data from the polymer/micelles mixtures displayed a strong structural peak and were remarkably identical for both ChEO 10 /CMD and ChEO 10 /C 12 EO 3 /CMD systems, suggesting a very similar type of network structure, independently of the initial size of the micelles. Overall, all the results taken together show a very high affinity between the polymer and the micelles and suggest a breakup of the WLM induced by CMD. The resulting network is constituted by polymeric chains connected by micellar aggregates through hydrophobic interactions between the micellar cholesterol cores and the pendent cholesterol moieties of the polymer.

Temperature‐Responsive Low Molecular Weight Ionic Liquid Based Gelator: An Approach to Fabricate an Anti‐Cancer Drug‐Loaded Hybrid Ionogel

“…The ionogel is supposed to be formed by encapsulating the water molecules within the network of percolated gelator inside the branched tubes. [21,55,57] The fibrous network is clearly visualized through FE-SEM image (Figure 5b) that confirmed that the fibres are of 1 to 3 μmin width and several micrometres in length, SANS data vide infra. [23,58,59] Thus, the transparent ionogel is made up of the long fibres, which on inter-digitating formed the 3D branched network.…”

“…In both the cases, opaque ionogel was converted into the transparent ionogel without any observable change in the viscosity of the ionogel unlike in the peptide based supramolecular gel, where the formation of viscous turbid solution was observed at slow rate of cooling. [18][19][20]55] The supramolecular ionogel with functionalized ILBS having bromide counterion also observed the phase transition in a similar fashion but it undergoes phase transition upon going from 50°C (transparent) to 25°C (opaque). [21] These results suggest that, the CetPySal forms supramolecular ionogel, that exhibits a temperature induced dynamic phase transition that is independent of heating rate.…”

Linear and Nonlinear Dynamic Behavior of Polymer Micellar Assemblies Connected by Metallo-Supramolecular Interactions

“…Supramolecular self-assembly is one of the most fascinating topics in soft matter. It gives synthetic materials some of the merits of biological systems, including self-healing properties, response to external stimuli, and the ability to reversibly modify stiffness as a reaction to external stress levels [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]. Supramolecular self-assembly strategy has been shown to work excellently for constructing dynamically bonded gels [19,20].…”

Controlled synthesis of new amphiphilic glycopolymers with liquid crystal grafts

“…In addition, biocompatibility, anticoagulant properties, and the good cell adhesion of cholesterol enable its use in drug delivery systems . Often, polymer chains are just modified by cholesteryl mesogen groups . Copolymers produced from a cholesterol‐based monomer have more rarely been reported …”

“…30,31 Often, polymer chains are just modified by cholesteryl mesogen groups. [32][33][34] Copolymers produced from a cholesterol-based monomer have more rarely been reported. 27,35,36 described, AChol has been used to produce amphiphilic poly(ethylene glycol)-b-poly(cholesteryl acryloyloxy ethyl carbonate)s (PEG-b-PAChol) and then authors studied their selfassembly properties.…”