Acta Mechanica

, Volume 229, Issue 9, pp 3715–3725 | Cite as

Measurement of the stiffening parameter for stimuli-responsive hydrogels

  • C. C. BenjaminEmail author
  • R. S. Lakes
  • W. C. Crone
Original Paper


A method of measuring the stiffening parameter \(\beta ^\circ \) for stimuli-responsive hydrogels using a simple tensile test is shown. 2-hydroxyethyl methacrylate (2-dimethylamino)ethyl methacrylate (HEMA–DMAEMA) stimuli-responsive hydrogels are examined using this method. HEMA–DMAEMA preconditioned in 3.0 pH, 7.0 pH, and 11.0 pH buffer solutions is studied experimentally. The stiffening parameter extracted at pH 7.0 is successfully used to predict the nonlinearity at pH 3.0 and 11.0. The measured stiffening parameter \(\beta ^\circ \) of the hydrogel is 0.870 ± 0.018, compared with 11.4 for ligament and 0.12–0.23 for brain.


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Dr. Benjamin would like to acknowledge helpful conversations that he had with Drs. Mehrdad Arjmand and Robert Witt on the conceptual application of implicit elasticity and future numerical methods. Additionally, I would like to acknowledge Dr. David Beebe for the use of his laboratory equipment and space when fabricating samples for testing and Dr. Alan Freed for his guidance with the conceptual understanding of tensor theory. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. (DGE-1256259). Support was also provided by the Graduate School, the Graduate Engineering Research Scholars (GERS) program, and the Vilas Life Cycle Professorship at the University of Wisconsin-Madison.


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© Springer-Verlag GmbH Austria, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Engineering Physics DepartmentUniversity of Wisconsin-MadisonMadisonUSA
  2. 2.Engineering Physics DepartmentUniversity of Wisconsin-MadisonMadisonUSA

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