Although synthetic hydrogels are very similar to biological tissues, they are normally very brittle and lack the ability to self-heal upon damage. Inspired by natural healing processes, different reversible molecular interactions have been used recently to generate self-healing hydrogels. Recently, we presented a simple strategy for the production of self-healing hydrogels via hydrophobic interactions.1-4Large hydrophobes such as stearyl methacrylate (C18) could be copolymerized with hydrophilic monomers like acrylamide, acrylic acid, N,N-dimethylacrylamide in aqueous solutions of worm-like surfactants. Incorporation of hydrophobic sequences within the hydrophilic polymer chains via micellar polymerization technique generates strong hydrophobic interactions, which prevent dissolution of the physical gels in water, while the dynamic nature of the junction zones provides homogeneity and self-healing properties.In this talk, I will discuss recent results from our lab on hydrogels with self-healing and shape-memory properties. By varying the hydrophobe content of the hydrogels, a transition from self-healing to shape memory behavior appears due to the organization of hydrophobic blocks in crystalline domains.5 The hydrogels exhibit 3 orders of magnitude change in the elastic modulus when the temperature changes between below and above the melting temperature of the crystalline domains. The blocky structure of the network chains formed by micellar polymerization is responsible for the drastic change in their mechanical properties and significant shape memory effect.1. D.C. Tuncaboylu, M. Sari, W. Oppermann, O. Okay, Macromolecules 44, 4997-5005 (2011)2. D.C. Tuncaboylu, M. Sahin, A. Argun, W. Oppermann, O. Okay, Macromolecules 45, 1991-2000 (2012)3. G. Akay, A. Hassan-Raeisi, D.C. Tuncaboylu, N. Orakdogen, S. Abdurrahmanoglu, W. Oppermann, O. Okay, Soft Matter 9, 2254-2261 (2013)4. U. Gulyuz, O. Okay, Soft Matter 9 (43), 10287-10293 (2013)5. C. Bilici, O. Okay, Macromolecules 46, 3125-3131 (2013)

Hydrogels with self-healing and shape-memory properties tuned by hydrophobic interactions

248th National Meeting (2014)

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