Water dispersible magnetite nanocluster coated with thermo‐responsive thiolactone‐containing copolymer

Abstract

This work focused on surface modification of magnetite nanoparticle (MNP) with poly(poly(ethylene glycol) monomethyl ether methacylate)-b-(poly(N-isopropylacrylamide)-st-poly(thiolactone acrylamide)), PPEGMA-b-(PNIPAAm-st-PTlaAm), diblock copolymer, synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization to obtain the particles having good water dispersible PPEGMA brushes, thermo-responsive PNIPAAm, and reactive thiolactone groups of PTlaAm.The thiolactone moiety in the copolymer can readily react with amino groups grafted on MNP surface and essentially induced the formation of MNP nanocluster.According to transmission electron microscopy (TEM), the size of the nanocluster ranged between 200 and 500 nm per cluster with 8 to 10 nm in diameter for each particle. Hydrodynamic diameter of the nanocluster significantly decreased as the dispersion temperature increased from 25 C to 45 C due to the shrinkage of thermo-responsive PNIPAAm when crossing its lower critical solution temperature (LCST). This stable nanocluster might be potentially used as a magnetic carrier for control release of entrapped entities with a thermally triggering mechanism. K E Y W O R D S magnetite, nanocluster, thermo-responsive, thiolactone, water dispersible

Thiolactone chemistry, a versatile platform for macromolecular engineering

“…The homopolymerization of N-(acryloyl) homocysteine-γ-thiolactone (Figure 5.2) was also carried out by RAFT in DMF, which solubilizes both monomer and homopolymer. 89 More complex polymer architectures were also prepare: PDEAEMA-b-P(NIPAM-st-TlaAm) block copolymer, 90 PPEGMA-b-P(NIPAM-st-TlaAm) block copolymer, 91 or double hydrophilic block copolymers (DHBC). 92 Another interesting monomer, maleimide thiolactone (Figure 5.3), was synthesized by Rudolph et al 78 This monomer was copolymerized with styrene and NIPAM via controlled radical polymerization using AIBN as initiator and a trithiocarbonate chain transfer agent in dioxane at 70°C.…”

“…5.2) was also carried out by RAFT in DMF, which solubilizes both monomer and homopolymer. 89 More complex polymer architectures were also prepare: PDEAEMA- b -P(NIPAM-st-TlaAm) block copolymer, 90 PPEGMA- b -P(NIPAM-st-TlaAm) block copolymer, 91 or double hydrophilic block copolymers (DHBC). 92 Another interesting monomer, maleimide thiolactone (Fig.…”

“…84–86 Similarly, the free thiols formed after the ring-opening reactions of thiolactone groups of various copolymers were used to coat amino-functionalized magnetite nanoparticles and cross-linked the polymer chain through disulfide bonds in order to induce the formation of magnetite nanoparticles clusters. 91…”

Research progress of iron-based catalysts for selective oligomerization of ethylene

“…Based on a large number of experimental studies, it indicates that the experimental effect of the catalyst supported by the carrier in the process of ethylene oligomerization is mainly affected by three factors including temperature, [123][124][125][126] concentration 127,128 and the pore diameter of the carrier. [129][130][131] In the polymerization reaction or oligomerization reaction of olen, catalysts are supported in two main ways.…”

Magnetic Nanoparticles Coated with Cationic Polymer and Label-Free Peptide Aptamer for Selective Adsorption with Bisphenol A

“…Therefore, coating MNP with functional polymers, e.g., poly(acrylic acid) [33] and poly(diethylamino)ethyl methacrylate (PDEAEMA) [20] and thermo-responsive polymers, e.g. poly(Nisopropylacrylamide) [34], is one of efficient strategies to prevent this undesirable agglomeration. Long chain polymers coating on MNP surface provided its steric stabilization and this can be designed to improve its stability and dispersibility in the media [23,[35][36][37][38][39].…”