Self-Oscillating Gels

Yoshida, Ryo

doi:10.1007/978-4-431-54767-9_5

Cited by 5 publications

(3 citation statements)

References 58 publications

(66 reference statements)

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“…The biophysical analogy (muscle behavior) and the notion of work production in cycles had already been pointed out at that time. In the mid 1990s, autonomous chemomechanical oscillators were created by driving chemoresponsive gels by oscillatory chemical reactions. , These reactions generated swelling–shrinking cycles, similar to heartbeats, without externally applied stimuli. The oscillatory reactions employed were either (1) pH oscillators (pH-responsive gels are easily available) that autonomously generated a periodically changing chemical environment around the gel − or (2) the Belousov–Zhabotinsky (BZ) reaction where a metal ion complex, needed as a catalyst for this oscillatory reaction and undergoing periodic redox changes, was grafted to a polymer network, and therefore periodic chemical changes occured only inside the gel.…”

Section: Introductionmentioning

confidence: 99%

Sustained Large-Amplitude Chemomechanical Oscillations Induced by the Landolt Clock Reaction

Horváth

2014

J. Phys. Chem. B

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Synergetic chemomechanical oscillators represent a fundamentally new class of oscillators, where a clock reaction, owning no oscillatory chemical kinetics, generates shrinking-swelling cycles in a chemoresponsive gel under appropriate fixed nonequilibrium boundary conditions. Sufficiently large size-changes are a condition for continually switching between a reacted and an unreacted chemical state in the gel through sufficiently large differences in the diffusion time between the environment and the core of the gel. Two former experimental demonstrations with acid autocatalytic reactions were frustrated either by complex behaviors (chlorite-tetrathionate system) or by side reactions with the gel matrix (bromate-sulfite system). With the Landolt (iodate-sulfite) reaction, regular large-amplitude chemomechanical oscillations can be sustained for more than a week. This enabled a fine study of the temperature and stoichiometry range of operation. I have identified several key steps that are experimentally essential to the systematic design of further synergetic oscillators. The robust realization of this type of self-organization in artificial systems is currently unique.

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Section: Introductionmentioning

confidence: 99%

Sustained Large-Amplitude Chemomechanical Oscillations Induced by the Landolt Clock Reaction

Horváth

2014

J. Phys. Chem. B

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“…The BZ reaction provides a model system to mimic a variety of complex processes, such as biological morphogenesis, in monodisperse microemulsions . In heterogeneous systems it facilitates investigation of the role of reaction-diffusion in pattern formation under conditions that are more relevant to morphogenesis, , and it can be used to develop chemomechanical systems. , …”

Section: Introductionmentioning

confidence: 99%

Post-Self-Assembly Cross-Linking to Integrate Molecular Nanofibers with Copolymers in Oscillatory Hydrogels

et al. 2013

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We study the use of post-self-assembly cross-linking to combine molecular nanofibers of hydrogelators with copolymers to generate oscillatory materials using the Belousov-Zhabotinsky reaction. The formation of nanofibers from designed hydrogelators provides multiple polymerizable sites for copolymerizing with N-isopropylacrylamide and for attaching a catalytic ruthenium bipyridine complex on the copolymer. The combination of supramolecular self-assembly with copolymerization offers a versatile and facile approach for generating soft materials that have large pores in the gel network and robust mechanical integrity. These larger pores facilitate the diffusion of the reactants and accelerate the chemical oscillation by about a factor of 4 relative to a poly(NIPAAm-Ru) gel that contains no molecular nanofibers.

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“…[95] The purpose of producing composite materials is to improve the general properties of the composite and incorporating inorganic particles (clay) to pNIPAM could improve several properties. The interesting properties of pNIPAM thermal response, [96] ability to absorb large volumes of water, [13] biocompatibility [76][97][98] make it a promising material for different applications, such as artificial soft tissues [99][100] [101] and drug delivery. [102] In pNIPAM, the thermoresponsive behaviour can be modified to be used as an injectable scaffold, where cells could suspend in the hydrogel in a flowing state above LCST, then gel will encapsulate the cells within its structure when temperature decreased below the LCST.…”

Section: Clay-polymer Nanocompositesmentioning

confidence: 99%

The synthesis, characterisation and rheological properties of clay-polymer nanocomposites

Judah¹

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This study aims to investigate the effect of different crosslinking agent and different crosslinking agent content on the material properties of the clay-polymer nanocomposite. A lot of materials were tried to be mixed to form a fully-reacted clay-polymer nanocomposite for the first time, which is a part of the novelty for this work. The overall properties governed by clay properties and clay/polymer relationship are prime aspects of this study. The Enhancement of significant properties of nanocomposites is a measure of clay platelets dispersion within the polymer matrix. Different approaches were adopted to understand the influence of clay properties on the nanocomposite; (i) by examining and comparing different clays as raw, dry, powder material using spectroscopy and thermogravimetric analysis (ii) mechanical examination of clay/water suspension of different clay types/grads, and different concentrations varying from 0.5 % - 10 % using rheological studies (iii) chemical and mechanical and morphological examination of Clay/Polymer nanocomposite with different clay types/grades, concentration, and polymers. The synthesis of such material addresses issues including heterogeneity, processability, injectability, crosslinking and mechanical stability. The synthesis requires no purification steps no specialist equipment, and basic typical components of crosslinked nanocomposite/hydrogels (water, monomer, clay and initiator). Morphological, pore size and scaffolding general arrangement which shows the effect of different crosslinking agents and crosslinking density were examined by Scanning Electron Microscope (SEM) to acquire information on wide/small pores are, diffusion kinetics in the system if required for further applications. The nature and elemental composition of the clay-polymer nanocomposites were determined by X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier Transfer Infrared (FTIR) spectroscopy. The water content in the dry clay-polymer nanocomposite was determined and examined by Thermogravimetric analysis (TGA). Mechanical and rheological properties of the result were examined using a rheometer that operates on different modes (as a Dynamic Mechanical Analysis (DMA) technique) to evaluate the structure, performance, strength, and mechanical modules of these nanocomposites under different rotational and oscillatory loads. This offers the opportunity to relate the differences to the clays and polymers the hydrogels were synthesised from.

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Self-Oscillating Gels

Cited by 5 publications

References 58 publications

Sustained Large-Amplitude Chemomechanical Oscillations Induced by the Landolt Clock Reaction

Sustained Large-Amplitude Chemomechanical Oscillations Induced by the Landolt Clock Reaction

Post-Self-Assembly Cross-Linking to Integrate Molecular Nanofibers with Copolymers in Oscillatory Hydrogels

The synthesis, characterisation and rheological properties of clay-polymer nanocomposites

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