Kinetics of solvent absorption and permeation through a highly swellable elastomeric network

Barrière, Benoı̂t; Leibler, Ludwik

doi:10.1002/polb.10341

Cited by 84 publications

(75 citation statements)

References 44 publications

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“…5, we recover our previous model for BZ gels (18,19,35) in the absence of light. We assume the dynamics of the polymer network to be purely inertialess (relaxational) (48), so that the forces acting on the deformed gel are balanced by the frictional drag due to the motion of the solvent. Hence, the corresponding force balance equation can be written as (35)…”

Section: Methodsmentioning

confidence: 99%

Reconfigurable assemblies of active, autochemotactic gels

Dayal

Kuksenok

Balazs

2012

Proc. Natl. Acad. Sci. U.S.A.

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Using computational modeling, we show that self-oscillating Belousov-Zhabotinsky (BZ) gels can both emit and sense a chemical signal and thus drive neighboring gel pieces to spontaneously self-aggregate, so that the system exhibits autochemotaxis. To the best of our knowledge, this is the closest system to the ultimate selfrecombining material, which can be divided into separated parts and the parts move autonomously to assemble into a structure resembling the original, uncut sample. We also show that the gels' coordinated motion can be controlled by light, allowing us to achieve selective self-aggregation and control over the shape of the gel aggregates. By exposing the BZ gels to specific patterns of light and dark, we design a BZ gel "train" that leads the movement of its "cargo." Our findings pave the way for creating reconfigurable materials from self-propelled elements, which autonomously communicate with neighboring units and thereby actively participate in constructing the final structure.self-oscillating gels | autochemotactic gels | autochemotactic self-organization S pecies ranging from single-cell organisms to social insects can undergo autochemotaxis, where the entities move toward a chemo-attractant that they themselves emit. This mode of signaling allows the organisms to form large-scale structures, with amoebas (1) and Escherichia coli (2) self-organizing into extensive multicellular clusters and termites constructing macroscopic mounds (3). Notably there are few equivalents of such autochemotactic-driven assembly in the synthetic world. Although researchers have devised a range of nano-and microscopic selfpropelled particles (4), hardly any exhibit autochemotaxis (5) that leads to the formation of extended structures (6). Although recent theoretical models provide insight into the autochemotaxis of a self-propelled walker (7) and active Brownian particles (8), these studies provide few guidelines for synthesizing specific materials that display autochemotactic self-organization. The latter materials would open new routes for dynamic, reconfigurable self-assembly, where self-propelled elements communicate with neighboring units and thereby actively participate in constructing the final structure. Herein, we use computational modeling to show that millimeter-sized polymer gels can display such self-sustained, autochemotatic behavior. In particular, we demonstrate that gels undergoing the self-oscillating Belousov-Zhabotinsky (BZ) reaction (9) not only respond to a chemical signal from the surrounding solution, but also emit this signal and thus, multiple neighboring gel pieces can spontaneously self-aggregate into macroscopic objects. These findings indicate that BZ gels can undergo a form of "selfrecombining": if a BZ gel is cut into distinct pieces and the pieces are moved relatively far apart, then their autochemotactic behavior drives the parts to move autonomously and recombine into a structure resembling the original, uncut sample (Fig. 1). We also show that the gels' coordinated motion can ...

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Section: Methodsmentioning

confidence: 99%

Reconfigurable assemblies of active, autochemotactic gels

Dayal

Kuksenok

Balazs

2012

Proc. Natl. Acad. Sci. U.S.A.

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“…Extraction of water from the newly formed hydrogel film into the substrate becomes difficult because it implies an elastic deformation of the cross-linked PVA network. Instead, it becomes more favorable for water to flow from the solution through the hydrogel film and into the substrate, as already described for gel membrane permeation (26). As a result, the solvent depletion process is displaced at the interface between the hydrogel film and the solution.…”

Section: Characterization Of Hydrogel Film Growth As a Function Of Sumentioning

confidence: 84%

Hydrogel films and coatings by swelling-induced gelation

Moreau

Chauvet

François

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Hydrogel films used as membranes or coatings are essential components of devices interfaced with biological systems. Their design is greatly challenged by the need to find mild synthesis and processing conditions that preserve their biocompatibility and the integrity of encapsulated compounds. Here, we report an approach to produce hydrogel films spontaneously in aqueous polymer solutions. This method uses the solvent depletion created at the surface of swelling polymer substrates to induce the gelation of a thin layer of polymer solution. Using a biocompatible polymer that self-assembles at high concentration [poly(vinyl alcohol)], hydrogel films were produced within minutes to hours with thicknesses ranging from tens to hundreds of micrometers. A simple model and numerical simulations of mass transport during swelling capture the experiments and predict how film growth depends on the solution composition, substrate geometry, and swelling properties. The versatility of the approach was verified with a variety of swelling substrates and hydrogel-forming solutions. We also demonstrate the potential of this technique by incorporating other solutes such as inorganic particles to fabricate ceramic-hydrogel coatings for bone anchoring and cells to fabricate cell-laden membranes for cell culture or tissue engineering. H ydrogel films are used in a number of biomedical applications like wound healing (1), drug delivery (1), antiadhesive membranes (2), soft-tissue reconstruction (3, 4), and cell culture (5). The quality of their interactions with biological tissues or entrapped cells is central to the performance of these systems. Although considerable advances have been made in synthesis (6) and processing (7) to tailor these interactions, the toxicity of by-products and the degradation caused by harsh processing conditions remain key issues (8), which can be overcome (9) but are often addressed at the cost of difficult synthesis or multistep processes. There is a great interest for simple, versatile, and in vivo-friendly methods to fabricate and modify hydrogels. We propose a strategy to design hydrogel films in mild conditions. This method could be used to produce freestanding hydrogel membranes or hydrogel coatings to functionalize other hydrogels.Our approach relies on the understanding of transport phenomena occurring near the surface of a polymer network swelling in a polymer solution. As an illustration, let us consider a flat polymer network with thickness H 0 immersed in a solution containing a volume fraction Φ 0 of free polymer chains, as depicted in Fig. 1A. When the solvent of the solution is also a solvent for the network, the network swells in a diffusive process. For early immersion times t, the increase in thickness ΔH is given by the following (10, 11):where H ∞ is the thickness at equilibrium swelling in the polymer solution and D 0 is a diffusivity coefficient depending on the dynamics of the network and of the solution. The systems of interest are those where the chains in solution do not penetrate...

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“…There has been a great number of debates about the form of the elastic terms without definite and universal answer. At our level of description and in the absence of precise experimental data -to be determined for each composition of gel -we shall follow the simple phenomenologic approach of Barrière and Leibler [35] based on the work of Bastide and Candau [45]. The authors assert that both the free energy by unit volume and the elastic modulus G(φ) scale like (φ/ψ) n .…”

Section: The Swelling Modelmentioning

confidence: 99%

“…Since the gel must be diluted (typically a few percent in the experiments), we take φ 0 = 0.05. To account for the shearing effects, we use equation 8 with C λ =1 as in [35]. To produce a significant swelling amount without a full volume transition, the Flory parameter is fixed to χ=0.515, i.e.…”

Section: Parameters Choicementioning

confidence: 99%

“…One does not need an oscillating reaction, only a much more common bistable one, to produce such a chemomechanical instability. Some models have been proposed to predict the dynamics of swelling in neutral gels without reaction [31][32][33][34][35][36][37] or with reaction [9,13,18,19]. In the second case, the chemical sensitivity of the gel is descibed by an assumed and somewhat arbitrary dependence of the Flory parameter χ, which gathers all the energetic interactions of monomer and solvent molecules, on the concentration of a chemical species.…”

Section: Introductionmentioning

confidence: 99%

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Oscillatory dynamics induced in polyelectrolyte gels by a non-oscillatory reaction: A model

Boissonade

2009

Eur. Phys. J. E

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Abstract. We develop a general model and the associated numerical algorithm to compute the swelling dynamics of chemo-responsive polyelectrolyte gels immersed in a reactive ionic solution kept at a nonequilibrium stationary state by a permanent feed of fresh reactants. Using an autocatalytic bistable but non-oscillatory reaction, namely, the bromate-sulfite reaction, we predict that a piece of hydrogel that swells/shrinks as a function of pH, can exhibit spontaneous mechanical and chemical oscillations. This constitutes the extension to realistic and experimentally feasible conditions of results previously obtained on a toy model with artificial swelling conditions.

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Kinetics of solvent absorption and permeation through a highly swellable elastomeric network

Cited by 84 publications

References 44 publications

Reconfigurable assemblies of active, autochemotactic gels

Reconfigurable assemblies of active, autochemotactic gels

Hydrogel films and coatings by swelling-induced gelation

Oscillatory dynamics induced in polyelectrolyte gels by a non-oscillatory reaction: A model

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