Self-Assembled Hydrogels Based on Poly-Cyclodextrin and Poly-Azobenzene Compounds and Applications for Highly Efficient Removal of Bisphenol A and Methylene Blue

Abstract

The excellent physical and chemical properties of cyclodextrin polymer (poly-CD)/azobenzene-modified polyacrylic acid (PAA-Azo) binary composite hydrogels have been designed and prepared. The prepared hydrogels were subjected to a variety of characterizations, including scanning electron microscopy, ultraviolet spectroscopy, circular dichroism spectroscopy, infrared spectroscopy, rheological properties, and specific surface area tests. It was found that the obtained hydrogels have the cross-linked three-dimensional porous network nanostructures, and the formed composite poly-CD/PAA-Azo hydrogel can basically be shear thinned and have good recovery performance. A process of gel–sol transition can occur when the gel has a stimulatory response under UV light irradiation. In addition, such excellent properties of hydrogels exhibit different mechanisms in the adsorption of organic molecules that are harmful to the environment, such as bisphenol A (BPA) and methylene blue (MB). The polymeric hydrogel serves as novel adsorbent agents to adsorb BPA via host–guest interaction and anchor MB via electrostatic interaction and hydrogen bonding.

A facile preparation method for new two-component supramolecular hydrogels and their performances in adsorption, catalysis, and stimuli-response

“…Within the tested pressure range, Gel-12 showed a hysteresis loop of the IV isotherm curve at p/p 0 ¼ 0.1-0.9, representing the mesoporous structure in Gel-12. 32 The BJH method was also used to evaluate the physical properties of the Gel-12.…”

A Review on the Design and Hydration Properties of Natural Polymer-Based Hydrogels

“…These processes can induce changes in polarity, steric hindrance, and polymer/crosslinking densities to affect the sol-gel transition (desolvated vs swollen or rod-to-coil conformations) of materials, and subsequent release of the guest payload (e.g., drugs and proteins). It is well known that azobenzene-based compounds exhibit typical trans → cis isomerization under UV irradiation and show an unfavorable cis→trans transition under visible light [ 90 , 91 ]. Peng and coworkers [ 92 ] have reported a photoresponsive hydrogel composed of trans azobenzene-modified dextran and CD-modified dextran for release of protein (cf.…”

From Supramolecular Hydrogels to Multifunctional Carriers for Biologically Active Substances

“…They have a hydrophilic external and relatively hydrophobic inner cavity. The small-cavity, α-CD, incorporates mainly linear guest molecules, while β-CD interacts with adamantane, azobenzene, ferrocene, cholesterol, and PEG ( Figure 5 ) [ 13 , 36 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ]. The CD units can be incorporated into cyclodextrin-polymers (e.g., polyrotaxanes), as well as being grafted to other polymer chains, e.g., alginate, HA, PEG, and PAA.…”

“…The CD units can be incorporated into cyclodextrin-polymers (e.g., polyrotaxanes), as well as being grafted to other polymer chains, e.g., alginate, HA, PEG, and PAA. Then, the guest molecules are attached to another polymer chain, and this promotes gel formation [ 11 , 13 , 59 , 60 , 61 , 62 , 63 ]. Among the synthetic macrocyclic cavitands are cucurbiturils, crown ethers, calixarenes, and pillararenes [ 58 ].…”