RII Track-4: Linking Chemistry and Mechanics of Soft Dynamic Interfaces

  • Pham, Jonathan (PI)

Grants and Contracts Details


Overview: Soft polymer interfaces underpin many important applications, from hydrogel medical adhesives and contact lenses, to organogel drug delivery systems and elastomeric pressure sensitive adhesives, like that used in the Apple HomePod vibration-dampening base. However, these examples are largely limited to materials with static properties, hindering advanced functions where smart, responsive, or transient interfaces are desirable. The proposed research aims to advance our knowledge on how to control interfaces of soft materials with dynamic mechanical properties, enabled by metal ion chelator crosslinkers and molecular architecture. The PI will cultivate a long-lasting collaboration with Prof. Niels Holten-Andersen, an expert in dynamic, soft materials chemistry at the Massachusetts Institute of Technology (MIT). The PI and one graduate student trainee will spend a combined total of five months per year during the fellowship to gain expertise in synthetizing dynamic polymer networks and characterizing how molecular scale parameters control bulk mechanical properties. Two material systems will be investigated. The first is a mussel-inspired histidine functionalized poly(ethylene glycol) (PEG) with varying molecular architectures, crosslinked with metallic ions. This offers a route to control both crosslinking dynamics and molecular structure. The other is a poly(ethylene glycol)-block-poly(propylene oxide) (PPO) copolymer, with a histidine functionalized PEG block. This system offers a unique route to incorporate physical crosslinks via hydrophobic PPO block aggregation, in addition to the dynamic metal ion crosslinkers, providing a hierarchy for property control. By utilizing these two systems, we will decouple how to control near- surface properties by molecular architecture and weight, physical crosslinking, and metal ion crosslinking dynamics. Intellectual merit: The proposed fellowship will lead to new understanding of how to tune materials chemistry to control interfacial and near-surface properties of soft dynamic materials. This will have a positive impact on the fields of solid and fluid mechanics, tribology, soft matter physics, polymer science, and biomaterials, as well as the general area of smart materials. The expected results from this work, a quantitative link between materials chemistry and interfacial properties, will enable and guide the design of soft dynamic surfaces. Moreover, such information will provide insight into the molecular picture of soft interfacial mechanics, a question that is currently receiving significant focus. It is anticipated that this study will provide the necessary information to develop new models for soft interfaces that account for dynamic chemical crosslinkers. Broader impacts: The proposed project will have a significant impact on understanding how to tune dynamic interfaces, which we expect will guide the development of unique biomaterials, coatings, adhesives, and membranes, all of which are important for a broad range of important applications, including tissue engineering, corrosion protection and commodity products. In addition, success of this fellowship will have an enormous impact on the PI's research trajectory. The PI is actively working at the intersection of polymer science and the physics/mechanics of soft interfaces; however tuning materials chemistry is not within his current repertoire of capabilities. By developing an expertise in dynamic soft materials through close collaboration with Prof. Holten-Andersen, the PI expects to return to his home institution empowered with transformative ideas that bridge chemistry, physics, and mechanics of soft materials. Moreover, this fellowship will enable both the PI and a student trainee to build relationships with world-renowned researchers at MIT in non-Newtownian fluids, polymer science, and surface science, which will raise the research profile of the PI, the student, and the University of Kentucky (UK). With UK's strength in healthcare research, the successful development of soft, dynamic interfaces is expected to lead to new collaborations with researchers from the UK medical campus, expanding the impact of this fellowship to UK and the overall well-being of Kentucky residents. Beyond the fellowship period, the PI anticipates sustaining his collaboration with Prof. Holten-Andersen no only on this project, but new ones, as well as develop new collaborations at both MIT and UK. Closely aligns with: Mathematical and Physical Science, Division of Materials Research, Polymers
Effective start/end date10/1/189/30/21


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