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Photoresponsive slide-ring hydrogels for on-demand modulation of mechanical properties
Hydrogel materials are crosslinked polymer networks with reversible swelling, tunable porosity, elasticity, toughness, and flexibility. Conventional hydrogels often suffer from weak mechanical properties and display brittle and unstable behaviour limiting their scope for load-bearing applications. Such networks consist of side-chain functionalized polymers, whose covalent crosslinks occur at fixed positions on the polymer backbone (Figure 1A). Upon deformation, tensile stress is concentrated on the closest neighboring crosslinks, eventually leading to their rupture and material failure. Hence, the molecular design of high-performance hydrogels with toughness and elasticity similar to rubber is an emerging area of research in the engineering of polymeric materials with applications towards robust medical materials or soft robotics.
To increase toughness and elasticity, slide-ring gels (SRG) have been developed, featuring enhanced energy dissipation. SRGs consist of slidable crosslinks that freely translocate along the polymer backbone. On a molecular level, two individual macrocycles that are threaded onto the polymer backbone are chemically linked and tie two separate polymer chains together (Figure 1B). These crosslinks are in shape of a figure-of-eight and can infuse materials with unique physicochemical and mechanical properties. When SRGs experience stress, the movable crosslinks help to equalize tension within the system, a phenomenon known as the “pulley effect” (Figure 1C).
The aim of this project is to explore a new synthetic pathway to generate SRGs that allow precise control of the number of crosslinks in the network, something that has to this day not been realized in a sufficient manner. Additionally with realization of this new pathway, we introduce a photo-responsivity into the materials, which will allow the spatiotemporal control of elastic properties of the material.
To increase toughness and elasticity, slide-ring gels (SRG) have been developed, featuring enhanced energy dissipation. SRGs consist of slidable crosslinks that freely translocate along the polymer backbone. On a molecular level, two individual macrocycles that are threaded onto the polymer backbone are chemically linked and tie two separate polymer chains together (Figure 1B). These crosslinks are in shape of a figure-of-eight and can infuse materials with unique physicochemical and mechanical properties. When SRGs experience stress, the movable crosslinks help to equalize tension within the system, a phenomenon known as the “pulley effect” (Figure 1C). The aim of this project is to explore a new synthetic pathway to generate SRGs that allow precise control of the number of crosslinks in the network, something that has to this day not been realized in a sufficient manner. Additionally with realization of this new pathway, we introduce a photo-responsivity into the materials, which will allow the spatiotemporal control of elastic properties of the material.
The main aim of this project is to explore a new synthetic pathway towards photoresponsive supramolecular slide-ring gels. If the above description has sparked your interest, please feel free to apply or contact us for more information!
The main aim of this project is to explore a new synthetic pathway towards photoresponsive supramolecular slide-ring gels. If the above description has sparked your interest, please feel free to apply or contact us for more information!
- Supervisor: Dr. Stefan Mommer
- Email: smommer@ethz.ch
- Site: www.stefanmommer.com
- To apply please include a short motivation letter, a CV and a full transcript of records
- Supervisor: Dr. Stefan Mommer - Email: smommer@ethz.ch - Site: www.stefanmommer.com - To apply please include a short motivation letter, a CV and a full transcript of records