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ABSTRACT: Polyelectrolyte gels are ductile elastic electroactive materials. They consist of a polymer network with bound charged groups
and a liquid phase with mobile ions. In water-based solutions, these gels show enormous swelling capabilities under the influence
of different types of stimulation, such as chemical, electrical, or thermal. In the present work, a coupled multi-field formulation
for polyelectrolyte gels using the finite element method is applied. Additionally to the three given fields—mechanical, electrical,
and chemical fields—the dissociation reactions of the bound charges in the gel phase are considered. In this study, chemical
stimulation (change of pH or salt concentration) is investigated for gels placed in solution baths. By changing the ambient
conditions, we are able to simulate both pH stimulation and change of salt concentration, and to give the change of the mobile
and bound ion concentrations, the electric potential, and the mechanical displacement.
KeywordsPolyelectrolyte gels–Coupled chemo-electro-mechanical multi-field formulation–Chemical stimulation–pH-sensitive gels–Dissociation reactions–Numerical simulation
Colloid and Polymer Science 01/2011; 289:535–544, doi: 10.1007/s00396-011-2404-1. · 2.33 Impact Factor
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ABSTRACT: In this paper, we present preliminary results showing the response of glucose-sensitive hydrogels, confined in micro-pressure sensors, to the changes in environmental glucose concentration. The glucose concentrations were incrementally varied between 20 and 0mM in 0.15M PBS solution at 7.4 pH and bovine serum at 7.4 pH at room temperature and response of the sensor was recorded. The micro sensors demonstrate a response time of 10 minutes in both PBS and serum. Tissue response after 55 days of subcutaneous implantation of a EtO sterilized sensor in mice is presented. The preliminary analysis of the surrounding tissue shows inflammation which is believed not to interfere with the sensor performance.
Engineering in Medicine and Biology Society (EMBC), 2010 Annual International Conference of the IEEE; 10/2010
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SPIE Smart Structures and Nondestructive Evaluation and Health Monitoring, San Diego, USA; 01/2010
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Technisches Messen. 01/2010; 77:179.
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Microsystem Technologies 01/2010; 16:703-715, doi: 10.1007/s00542-009-0978-z. · 0.93 Impact Factor
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Journal of Intelligent Material Systems and Structures 01/2009; 20(12):1483-1492, doi:10.1177/1045389X09105236. · 1.95 Impact Factor
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ABSTRACT: “Stimuli-responsive” or “smart” hydrogels are capable of reversibly converting chemical energy into mechanical one and therefore they are widely used as sensitive materials for chemical sensors. However, nonlinear effects such as hysteresis and drift are observed in the swelling behaviour of the hydrogels complicating the calibration procedure for the sensor and affecting the signal reproducibility. In the present work, in order to realize pH and temperature sensors with high signal reproducibility and high long-term stable sensor sensitivity, the complicated kinetics of gel swelling/deswelling processes has been analysed and the origin of the hysteresis nonlinearities has been elucidated.
Journal of Intelligent Material Systems and Structures 01/2009; 20:949-961, doi:10.1177/1045389X08101562. · 1.95 Impact Factor
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Procedia Engineering. 25:1141-1144.
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