Composite microspheres with PAM microgel core and polymerisable surfactant/polyoxometalate complexes shell

Abstract

The composite microspheres of poly(acrylamide) microgels (PAM) surfacely covered with [3-(acryloylamino)propyl]dodecyldimethyl ammonium-tungstophosphate complexes (APDDAB-PWA) were synthesized by using an ion-exchange reaction between APDDAB located within the porous PAM microgels and PWA in aqueous solution. The morphology and component of the composite microspheres were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, respectively. The results indicated that PAM/ APDDAB-PWA composite microsphere with different hierarchical surface structures could be obtained by controlling the weight ratio of APDDAB to PAM microgels, cross-linking degree of PAM microgels, the amount of PWA reacted with APDDAB in PAM/APDDAB, and solvent-washing process. Although the surface morphologies of the composite microspheres in detail were different, a general feature was of the core-shell structure and the wrinkly surface covered with APDDAB-PWA particles. The formation of the wrinkly surface is attributed to the difference in shrink between inside and outside of PAM microgel frameworks, and the formation of APDDAB-PWA small particles originates from the reaction between APDDAB aggregation and PWA. This composite microsphere with PAM hydrogel core is suitable to store water-soluble substances, and the shell composed of the surfactant/Keggin-type polyoxometalate complexes is not only amphiphilic but also catalytic. Additionally, PAM/APDDAB-PWA composite microspheres with big size and APDDAB-PWA particles with small size make the composite microspheres not only easy for separation but also beneficial for catalysis. These properties have been verified by the application of PAM/APDDAB-PWA composite microspheres to the deep desulfurization of fuel oil. This material provides an example to construct microreactors with new structure used in diphase catalytic reaction.

Tailoring pH-responsive acrylic acid microgels with hydrophobic crosslinks for drug release

“…6,22 Commonly, hydrophilic microgels are fabricated and then modified to produce amphiphilic microgels by covalently or electrostatically binding amphiphilic or hydrophobic moieties. 1,4,7,[18][19][20][21] In this study we have used a microfluidic device to form droplets that were subsequently polymerised and hydrolysed to fabricate amphiphilic microgels that were based on acrylic acid (AA, ionisable and hydrophilic) and hydrophobic crosslinks based on the hydrophobic crosslinker ethylene glycol dimethacrylate (EGDMA). The application of a microfluidic platform offers the advantages of generating droplets, and consequently microgels, of narrower size distribution, while the size of the droplets can be tailored by varying the flow rates.…”

“…If the CP is based on oil or an organic solvent, the hydrophobic reagents will diffuse from the droplets to the CP. Thus, amphiphilic microgels are usually prepared using postmodifications 1,4,7,[17][18][19][20][21] and/or multi-step procedures. 6,22 Commonly, hydrophilic microgels are fabricated and then modified to produce amphiphilic microgels by covalently or electrostatically binding amphiphilic or hydrophobic moieties.…”

Microhydrogel surface-supported quaternary ammonium peroxotungstophosphate as reusable catalytic materials for oxidation of DBT

“…Employing poly(N-isopropylacrylamide-co-acrylic acid), poly(N-isopropylacrylamide-comethacrylic acid), polyacrylamide, and poly(N-isopropylacrylamide) 1381-5148/$ -see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.reactfunctpolym.2011.01.003 microgels as templates, several interesting polymeric composite microspheres have been successfully synthesized [16][17][18][19][20][21]. After combing our previous research and the protocol for the construction of the integration microsphere with the water pool and surfactant shell used in biphasic catalytic reactions, composite microspheres with PAM microgel cores and shells of polymerizable surfactant/polyoxometalate complexes were synthesized.…”

Synthesis and Characterization of a Thermoresponsive Polyoxometalate–Polymer Hybrid

“…[6] The strategies used for their preparation have been based on physical blending (however the hybrids lack stability), [7] electrostatic interactions (limited to positively charged polyelectrolytes), [8] physical encapsulation (through ionic interactions) of POMs by in situ polymerization of cationic surfactants bearing polymerizable groups, [9,10] and the covalent bonding of both partners. This last strategy is especially appealing as it is versatile and guarantees the chemical stability of the resulting hybrids.…”