Multi-Effect-Coupling pH-Electric-Stimuli (MECpHe) Model for Smart Hydrogel Responsive to pH-Electric Coupled Stimuli



In general, the mechanism of the response of smart hydrogel to the externally applied electric field stimulus is similar to that to the pH stimulus of environmental solution (Tanaka, 1981; Qiu and Park, 2001). When an electric field is imposed to the bath solution where the hydrogel is immersed, the mobile ions diffuse between the hydrogel and the surrounding solution. The diffusion gives rise to the difference of ionic concentrations between the interior hydrogel and exterior solution, because of the fixed charge groups bound to the crosslinked macromolecular chains. As a result, an osmotic pressure is generated due to the concentration difference, which drives the swelling or shrinking of the hydrogel. Then the deformation of the hydrogel results in the redistribution of the diffusive ions and the fixed charge groups within the hydrogel, which causes new ionic diffusion and then the hydrogel deforms again. The recurrent kinetics continues and finally stops when the hydrogel reaches an equilibrium state, by converting the chemical energy to the mechanical one.


Osmotic Pressure Average Curvature Electric Voltage Ionic Valence Kirchhoff Stress Tensor 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Hua Li
    • 1
  1. 1.College of Engineering School of Mechanical & Aerospace EngineeringNanyang Technological UniversitySingaporeSingapore

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