Self-oscillating core/shell microgels: effect of a crosslinked nanoshell on autonomous oscillation of the core

Suzuki, Daisuke; Yoshida, Ryo

doi:10.1038/pj.2010.28

Cited by 32 publications

(26 citation statements)

References 39 publications

(64 reference statements)

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“…In addition to analyzing the polymer solutions, we prepared submicron-sized poly(NIPAAm-co-Ru(bpy) 3 ) gel beads by surfactant-free aqueous precipitation polymerization, and analyzed the oscillating behavior of the microgel dispersions [20][21][22][23][24]. At low temperatures (20-26.5 • C), on raising the temperature, the amplitude of the oscillation became larger.…”

Section: Self-oscillating Polymer Solution and Microgel Dispersion Asmentioning

confidence: 99%

“…This self-oscillating property makes microgels more attractive for future developments such as microgel assembly, optical and rheological applications, etc. It is clear that the macroscopic self-oscillating gel prepared by crosslinking the assembled microgels exhibits a faster response and leads to larger amplitude of swelling-deswelling oscillation, and recently, self-oscillating core/shell microgels composed of the selfoscillating microgel as a core and PNIPAAm or poly(N-isopropylmethacrylamide) (PNIPMAm) as a shell [22]. The effects of crosslinked nanoshells covering selfoscillating microgels on their oscillating behaviors were investigated.…”

Section: Self-oscillating Polymer Solution and Microgel Dispersion Asmentioning

confidence: 99%

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Biomimetic Self‐Oscillating Polymer Gels

Yoshida¹

2013

Intelligent Stimuli‐Responsive Materials

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There have been many studies on stimuli-responsive polymer gels that exhibit a reversible swelling-deswelling change in response to environmental changes such as solvent composition, temperature, and pH change. In contrast, we have developed a novel "self-oscillating" polymer gel that exhibits autonomous mechanical oscillation without an external control in a completely closed solution ( Fig. 11.1). For the design of the gel, the Belousov-Zhabotinsky (BZ) reaction, which is wellknown for exhibiting temporal and spatiotemporal oscillating phenomena [1, 2], was focused. We attempted to convert the chemical oscillation of the BZ reaction into a mechanical change in gels and generate an autonomous swelling-deswelling oscillation under non-oscillatory outer conditions. A copolymer gel consisting of N-isopropylacrylamide (NIPAAm) and ruthenium tris(2,2 -bipyridine) (Ru(bpy) 3 ), acting as a catalyst for the BZ reaction, was prepared ( Fig. 11.2a). When the poly(NIPAAm-co-Ru(bpy) 3 ) gel is immersed in the catalyst-free BZ solution, the reaction occurs in the gel by the catalytic function of the polymerized Ru(bpy) 3 (Fig. 11.2c). The redox changes of the polymerized catalyst moiety (Ru(bpy) 3 2+ Ru(bpy) 3 3+ ) change the volume phase transition temperature as well as the swelling ratio of the gel because the hydrophilicity of the polymer chains increases at the oxidized Ru(III) state and decreases at the reduced Ru(II) state (Fig. 11.2b). As a result, the gel exhibits an autonomous swelling-deswelling oscillation with the redox oscillation in the closed solution under constant condition (Fig. 11.2d).

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Section: Self-oscillating Polymer Solution and Microgel Dispersion Asmentioning

confidence: 99%

Section: Self-oscillating Polymer Solution and Microgel Dispersion Asmentioning

confidence: 99%

Biomimetic Self‐Oscillating Polymer Gels

Yoshida¹

2013

Intelligent Stimuli‐Responsive Materials

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“…[34][35][36][37][38][39][40] Figure 9B shows the oscillation profiles of transmittance for the microgel dispersions. At low temperatures (20-26.5 1C), on raising the temperature, the amplitude of the oscillation became larger.…”

Section: Self-flocculating/dispersing Oscillation Of Microgelsmentioning

confidence: 99%

“…32 In addition, submicron-sized self-oscillating microgel beads were prepared by a precipitation polymerization method. [35][36][37][38][39][40] To realize nanoactuators that exhibit autonomous oscillation on a nanometer scale (nanooscillator), using the linear polymer chain or microgels, their oscillating behavior was investigated through the optical transmittance or viscosity changes [39][40][41] of the polymer solution or microgel dispersions.…”

Section: Introductionmentioning

confidence: 99%

Development of self-oscillating polymers and gels with autonomous function

Yoshida

2010

Polym J

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In this study, polymers with an autonomous self-oscillating function were examined to obtain a novel biomimetic polymer. The author succeeded in developing a novel self-oscillating polymer and gel by using the oscillating reaction called the Belousov-Zhabotinsky (BZ) reaction, which is recognized as a chemical model for understanding several autonomous phenomena in biological systems. The self-oscillating polymer is composed of a poly(N-isopropylacrylamide) network in which the catalyst for the BZ reaction is covalently immobilized. Under the coexistence of reactants, the polymer undergoes spontaneous cyclic soluble-insoluble changes or swelling-deswelling changes (in the case of gel) without any on-off switching of external stimuli. Several kinds of functional material systems using self-oscillating polymer and gel, such as biomimetic actuators and mass transport surfaces, are expected.

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“…Microscopic gels have also been widely studied, 8 and nanogels, in particular, are interesting research objects from the point of view of their applications. [9][10][11] According to IUPAC, 12 a nanogel is defined as a particle of gel of any shape with an equivalent diameter of approximately 1-100 nm.…”

Section: Introductionmentioning

confidence: 99%

Arm-replaceable star-like nanogels: arm detachment and arm exchange reactions by dynamic covalent exchanges of alkoxyamine units

Amamoto

Kikuchi

Otsuka

et al. 2010

Polym J

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The arms of star-like nanogels were replaced by means of dynamic covalent exchange processes, and arm detachment and arm exchange reactions were successfully accomplished. Each star-like nanogel with alkoxyamine units at its branching points consisted of arms of poly(methyl methacrylate) (PMMA) synthesized by atom transfer radical polymerization, and a core of poly(divinylbenzene), synthesized by nitroxide-mediated radical polymerization using functionalized PMMA as a macroinitiator. The alkoxyamine groups were capable of serving as radically exchangeable units. Arm detachment reactions were carried out through a radical crossover reaction by heating the star-like nanogels with an excess of a small molecule alkoxyamine, whereas arm exchange reactions were performed by heating nanogels with higher molecular weight PMMA functionalized with alkoxyamine units at the chain ends. The molecular weights and sizes of the star-like nanogels were examined by gel permeation chromatography-multiangle light scattering and small-angle X-ray scattering measurements, respectively, and the shapes of nanogels were characterized by means of scanning force microscopy.

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Self-oscillating core/shell microgels: effect of a crosslinked nanoshell on autonomous oscillation of the core

Cited by 32 publications

References 39 publications

Biomimetic Self‐Oscillating Polymer Gels

Biomimetic Self‐Oscillating Polymer Gels

Development of self-oscillating polymers and gels with autonomous function

Arm-replaceable star-like nanogels: arm detachment and arm exchange reactions by dynamic covalent exchanges of alkoxyamine units

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