On the blistering of thermo-sensitive hydrogel: the volume phase transition and mechanical instability

Shen, Tong; Kan, Jian; Benet, Eduard; Vernerey, Franck J.

doi:10.1039/c9sm00911f

Cited by 7 publications

(13 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While these initial dynamics may be difficult to experimentally observe, our simulations show that these regions quickly coarsen and give rise to alternating zones of large and small compressive stress. In higher dimensions, this highly non-uniform stress distribution is likely to trigger instabilities leading to complex patterns as previously observed in experiments, for example, by Tanaka [3] and more recently by Shen et al [73] and Chang et al [74].…”

Section: Discussionsupporting

confidence: 52%

A kinetic model of a polyelectrolyte gel undergoing phase separation

Celora,

Hennessy,

Münch

et al. 2021

Preprint

View full text Add to dashboard Cite

In this study we use non-equilibrium thermodynamics to systematically derive a phase-field model of a polyelectrolyte gel coupled to a hydrodynamic model for a salt solution surrounding the gel.The governing equations for the gel account for the free energy of the internal interfaces which form upon phase separation, the nonlinear elasticity of the polyelectrolyte network, and multicomponent diffusive transport following a Stefan-Maxwell approach. The time-dependent model describes the evolution of the gel across multiple time and spatial scales and so is able to capture the large-scale solvent flux and the emergence of long-time pattern formation in the system. We explore the model for the case of a constrained gel undergoing uni-axial deformations. Numerical simulations show that rapid changes in the gel volume occur once the volume phase transition sets in, as well as the triggering of spinodal decomposition that leads to strong inhomogeneities in the lateral stresses, potentially leading to experimentally visible patterns.

show abstract

Section: Discussionsupporting

confidence: 52%

A kinetic model of a polyelectrolyte gel undergoing phase separation

Celora,

Hennessy,

Münch

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Temperature, light Mesogen-driven network deformation Oseen, 1933;Frank, 1958;Ericksen, 1961;Stephen and Straley, 1974;De Gennes and Prost, 1993;Terentjev, 1996, 2007;Finkelmann et al, 2001;Ikeda et al, 2007;Ohm et al, 2012;Jiang et al, 2013;White and Broer, 2015;Yakacki et al, 2015;Guin et al, 2018;McBride et al, 2018;Ula et al, 2018;Shang et al, 2019 Gels Hydrogels Humidity, other fluids Swelling-driven response Flory, 1950;Tanaka and Fillmore, 1979;Hong et al, 2008;Zhu et al, 2018;Agarwal et al, 2019 PNIPAm Humidity, other fluids, temperature change Temperaturedependent swelling-driven response Afroze et al, 2000;Yan and Tsujii, 2005;Deshmukh et al, 2013;Li et al, 2015;Vernerey and Shen, 2017;Işikver and Saraydin, 2019;Shen et al, 2019;Wang et al, 2020 PNIPAm, poly(N-isopropylacrylamide).…”

Section: Polymers With Conformational Instabilitiesmentioning

confidence: 99%

“…In these problems the fluid mass transport and the network deformation are coupled phenomena (Tanaka and Fillmore, 1979;Chirani et al, 2015). Gels have been employed also for developing smart and responsive materials to be used in flexible electronics, actuation, and soft robotics (Shen et al, 2017(Shen et al, , 2019Rong et al, 2018). For instance, hydrogels can mimic the pressure-driven trophic motion in plants and fungi and have been used to create light, humidity, or biological sensors capable of movement (Ionov, 2014).…”

Section: Swelling-driven Response Of Gelsmentioning

confidence: 99%

“…Hydrogels are capable of experiencing a significant change of volume by swelling/deswelling when subjected to external stimuli. For instance, thermosensitive PNIPAm hydrogels are well known for their capability to undergo a sharp volume-phase transition around the lower critical swelling temperature (LCST) of 305 K (Afroze et al, 2000;Vernerey and Shen, 2017;Shen et al, 2019). When the temperature quickly rises around the LCST, the hydrogel undergoes a reversible transition from a swollen state to a shrunken dehydrated state, losing more than 90% of its volume (Figure 7A).…”

Section: Pnipam Hydrogel-based Actuatorsmentioning

confidence: 99%

See 1 more Smart Citation

Smart Polymers for Advanced Applications: A Mechanical Perspective Review

2020

Self Cite

View full text Add to dashboard Cite

Responsive materials, as well as active structural systems, are today widely used to develop unprecedented smart devices, sensors, or actuators; their functionalities come from the ability to respond to environmental stimuli with a detectable reaction. Depending on the responsive material under study, the triggering stimuli can have a different nature, ranging from physical (temperature, light, electric or magnetic field, mechanical stress, etc.), chemical (pH, ligands, etc.), or biological (enzymes, etc.) type. Such a responsiveness can be obtained by properly designing the meso-or macroscopic arrangement of the constitutive elements, as occurs in metamaterials, or can be obtained by using responsive materials per se, whose responsiveness comes from the chemistry underlying their microstructure. In fact, when the responsiveness at the molecular level is properly organized, the nanoscale response can be collectively detected at the macroscale, leading to a responsive material. In the present article, we review the enormous world of responsive polymers, by outlining the main features, characteristics, and responsive mechanisms of smart polymers and by providing a mechanical modeling perspective, both at the molecular as well as at the continuum scale level. We aim at providing a comprehensive overview of the main features and modeling aspects of the most diffused smart polymers. The quantitative mechanical description of active materials plays a key role in their development and use, enabling the design of advanced devices as well as to engineer the materials' microstructure according to the desired functionality.

show abstract

“…Experiments on these thermo-responsive gels have suggested that there is a difference between the behaviour of a homogeneous gel when swelling, compared to when shrinking: dynamic swelling has been observed to equilibrate exponentially, whereas the dynamics of a shrinking gel appears more complicated and can exhibit an instability that forms lobe-like structures (Sato Matsuo & Tanaka 1988). Temperature changes beyond transition have been observed to cause separation into distinct swollen and shrunken states along the length of a cylinder, with an appearance similar to the fluid-dynamical Rayleigh-Plateau instability (Matsuo & Tanaka 1992), as well as through the appearance of surface blisters that can cause deformation of rods and tori (Chang et al 2018;Shen et al 2019).…”

Section: Introductionmentioning

confidence: 99%

The swelling and shrinking of spherical thermo-responsive hydrogels

Butler

Montenegro‐Johnson

2022

J. Fluid Mech.

View full text Add to dashboard Cite

Thermo-responsive hydrogels are a promising material for creating controllable actuators for use in micro-scale devices, since they expand and contract significantly (absorbing or expelling fluid) in response to relatively small temperature changes. Understanding such systems can be difficult because of the spatially and temporally varying properties of the gel, and the complex relationships between the fluid dynamics, elastic deformation of the gel and chemical interaction between the polymer and fluid. We address this using a poro-elastic model, considering the dynamics of a thermo-responsive spherical hydrogel after a sudden change in the temperature that should result in substantial swelling or shrinking. We focus on two model examples, with equilibrium parameters extracted from data in the literature. We find a range of qualitatively different behaviours when swelling and shrinking, including cases where swelling and shrinking happen smoothly from the edge, and other situations that result in the formation of an inwards-travelling spherical front that separates a core and shell with markedly different degrees of swelling. We then characterise when each of these scenarios is expected to occur. An approximate analytical form for the front dynamics is developed, with two levels of constant porosity, that well-approximates the numerical solutions. This system can be evolved forward in time, and is simpler to solve than the full numerics, allowing for more efficient predictions to be made, such as when deciding dosing strategies for drug-laden hydrogels.

show abstract

On the blistering of thermo-sensitive hydrogel: the volume phase transition and mechanical instability

Abstract: This paper explores the physical mechanisms responsible for the appearance of small blisters on the surface of temperature sensitive hydrogels as they deswell rapidly during their volume phase transition.

Cited by 7 publications

References 49 publications

A kinetic model of a polyelectrolyte gel undergoing phase separation

A kinetic model of a polyelectrolyte gel undergoing phase separation

Smart Polymers for Advanced Applications: A Mechanical Perspective Review

The swelling and shrinking of spherical thermo-responsive hydrogels

Contact Info

Product

Resources

About