Synthesis and Characterization of Maltose-Based Amphiphiles as Supramolecular Hydrogelators

Low molecular mass amphiphilic glycolipids have been prepared by linking a maltose polar head and a hydrophobic linear chain either by amidation or copper(I)-catalyzed azide–alkyne [3 + 2] cycloaddition. The liquid crystalline properties of these amphiphilic materials have been characterized. The influence of the chemical structure of these glycolipids on the gelation properties in water has also been studied. Glycolipids obtained by the click coupling of the two components give rise to stable hydrogels at room temperature. The fibrillar structure of supramolecular hydrogels obtained by the self-assembly of these gelators have been characterized by electron microscopy. Fibers showed some torsion, which could be related with a chiral supramolecular arrangement of amphiphiles, as confirmed by circular dichroism (CD). The sol–gel transition temperature was also determined by differential scanning calorimetry (DSC) and NMR

Supramolecular Hydrogels Based on Glycoamphiphiles: Effect of the Disaccharide Polar Head

Supramolecular hydrogelators based on amphiphilic glycolipids have been prepared by clicking different sugar polar heads to a hydrophobic linear chain by copper­(I)-catalyzed azide–alkyne [3 + 2] cycloaddition. The influence of the sugar polar head on the gelation properties in water has been studied, and the liquid crystalline properties of the amphiphilic materials have also been characterized. Stable hydrogels at room temperature have been obtained and the fibrillar supramolecular structures formed by the self-assembly have been studied by different microscopic techniques on the dried gel (xerogel) and hydrated conditions in order to characterize the micro- and nanostructures. Self-assembly gives rise to supramolecular ribbons with a torsion that is related to a chiral supramolecular arrangement of amphiphiles. The formation of an opposite helical arrangement of the ribbons has been found to depend on the sugar polar head. This fact was confirmed by circular dichroism (CD)

Thermoresponsive Properties of PNIPAM-Based Hydrogels: Effect of Molecular Architecture and Embedded Gold Nanoparticles

Thermoresponsive hydrogels were successfully prepared from poly­(<i>N</i>-isopropylacrylamide)-based polymers with different architectures (linear, branched, or hyperbranched). The macromolecular architectures strongly influence the internal structure of the hydrogels, therefore modulating their thermoresponsive and rheological properties. These hydrogels were used for the in situ synthesis of gold nanoparticles. Significant changes in hydrogel microstructures and in average pore size due to the presence of gold nanoparticles were observed. Additionally, their presence significantly increases both the mechanical strength and the toughness of the hydrogel networks