• DOI:10.1002/adma.201004230
• Corpus ID: 205239458

Tunable, High Modulus Hydrogels Driven by Ionic Coacervation

@article{Hunt2011TunableHM,
  title={Tunable, High Modulus Hydrogels Driven by Ionic Coacervation},
  author={Jasmine N. Hunt and Kathleen E. Feldman and Nathaniel A. Lynd and Joanna Deek and Luis M. Campos and Jason M. Spruell and Blanca M. Hernandez and Edward J. Kramer and Craig J. Hawker},
  journal={Advanced Materials},
  year={2011},
  volume={23}
}

• Jasmine N. Hunt, Kathleen E. Feldman, +6 authors C. Hawker
• Published 24 May 2011
• Materials Science
• Advanced Materials

The need for robust and responsive hydrogels in numerous pharmaceutical, biomedical, and industrial applications has motivated intense research efforts in these important polymeric materials. [ 1–6 ] The defi ning feature of hydrogels is that the vast majority of their mass consists of water, yet they still exhibit solid-like mechanical properties due to the presence of a three-dimensional network structure that, classically, is created through in situ covalent bond formation between multifunctional, reactive precursors. [ 6 , 7 ] A wide variety of chemistries have been utilized for covalent crosslinking of hydrogel-forming materials, e.g. free radical polymerization, Michael addition, and thiol-ene coupling, with the resulting hydrogels having good mechanical properties arising from the strong covalently bonded framework. [ 1 , 6–10 ] Limitations of the covalent approach are that the hydrogels are not re-moldable once formed, have limited responsiveness to external stimuli, and may require organic co-solvents/reagents during their formation. To overcome these limitations, hydrogels formed through non-covalent, physical associations arising from intermolecular interactions, in lieu of covalent crosslinks, have attracted signifi cant interest recently, particularly as responsive materials and injectable gels. [ 5 , 6 ] Typically, a drawback of such physically-associated hydrogels is their poor mechanical properties due to generally weak intermolecular interactions. [ 11 , 12 ] However, recent work by Gong et al. [ 13 ] and Yasuda et al . [ 14 ] on double network gels and Wang et al . [ 15 ] on the development of “aquamaterials” has demonstrated that signifi cant improvement in hydrogel mechanical properties is possible through careful design of the intermolecular interactions and length-scales between crosslinks or physical associations. In addressing new strategies to yield high performance, physically associated hydrogels, the role of dynamic materials formed via electrostatic interactions serves as a powerful model. While block copolyelectrolytes are widely used in the construction of hydrogel materials, the majority of these systems are based on block copolymers where the ionic blocks serve as the water soluble component and neutral, hydrophobic blocks