Thermally responsive complex polymer networks containing Fe₃O₄ nanoparticles: Composition/morphology/property relationship

Abstract

In this research, the synthesis and properties of thermally responsive complex polymer networks containing Fe3O4 nanoparticles were studied. First, a stable ferrofluid containing Fe3O4 nanoparticles was synthesized via a coprecipitation method in the presence of a poly(acrylic acid) oligomer. This stable ferrofluid could mix well with water‐soluble monomers by the adjustment of its pH value. Second, a thermally responsive copolymer was synthesized in the presence of the ferrofluid containing Fe3O4 nanoparticles to obtain the complex polymer networks. By the adjustment of the pH value, the ferrofluid could remain stable in the polymerization system, in which N‐isopropylacrylamide (NIPAAm) and methacrylic acid (MAA) were used as comonomers to provide thermoresponsive properties and acid groups and ammonium persulfate and sodium metabisulfite were used as the redox initiator system. Several variables, such as the molar ratio of MAA to NIPAAm, the concentrations of the monomers and crosslinking agent, the addition of an ammonium solution, and the content of the ferrofluid, were studied in this polymerization. Their effects on the morphology, structure, polymerization rate, and thermal properties of the complex polymer networks were discussed. The swelling and thermoresponsive behaviors of the complex polymer networks containing Fe3O4 nanoparticles were also studied, and the composition–morphology–property relationship was established. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5923–5934, 2005

Novel electrically conductive and ferromagnetic composites of poly(aniline‐co‐aminonaphthalenesulfonic acid) with iron oxide nanoparticles: Synthesis and characterization

“…The temperature range of 30-8008C is usually sufficient to determine decomposition temperatures of composites and wt % of Fe 3 O 4 in the composites. 28,29,34,40,50 Beyond 8008C, significant changes was not observed. PANI or SPAN-ANSA can undergo degradation via two or three steps: expulsion of absorbed water/moisture, decomposition of dopants or SO À 3 units, and decomposition of polymer chains.…”

“…The hysteresis of the magnetization was obtained with an applied field between 15 kOe and 25 kOe; these measurements were carried out at 300 K. Fe(III) ions to Fe 3 O 4 nanoparticles involves through a sequence of complex steps including deprotonation, hydrolysis, oxidation, precipitation, nucleation, crystallization, dehydroxylation, and/or dehydration. 40 Fe 2þ þ 2Fe 3þ þ 8OH À À! FeðOHÞ 2…”

Synthesis and properties of thermoresponsive magnetic polymer composites and their electrospun nanofibers

“…For DLF/PNIPAAm-1 and DLF/PNIPAAm-2 sample solutions at 5 wt % of solid content, LCSTs decreased to 31.7 and 31. 25 C, respectively. The interaction between carboxylic acid and amide groups, which belonged to DLF and PNIPAAm, respectively, caused the LCST of DLF/PNIPAAm to shift to the lower temperature.…”

“…Subsequently, the polymer solution was dialyzed for 3 days and dried by lyophilization to obtain the PNIPAAm powder. 25 DLF/PNIPAAm polymer solutions with different compositions were prepared by mixing appropriate amount of DLF solution with PNIPAAm solution (Table 1). After the mixture was dried in the oven, the DLF/PNIPAAm composites were obtained and then were analyzed by using TGA and SQUID.…”

Theoretical description of a responsive magneto-hydrogel transduction principle

“…The hydrogel essentially exists of superparamagnetic colloidal particles, further referred to as nanoparticles that are fixed inside the analyte-sensitive hydrogel network. A similar hydrogel, albeit thermo-responsive, has recently been reported in the literature [10]. The hybrid hydrogel in this study needs to be deposited and anchored onto a substrate in which a GMR element is embedded.…”