In order to tackle modern societal problems centered on sustainability, biomedicine, engineering, and energy, chemists are tasked with the opportunity to create new genres of matter. An increased interplay of fundamental chemistry and applied material science will undoubtedly give rise to the next generation of polymeric materials. Fortunately, the Golder Research Team is in a unique position to utilize synthetic chemistry to build novel macromolecular architectures that address these challenges. The discovery of structural motifs spanning a variety of size regimes requires innovative approaches to construct and link functional building blocks, thus requiring an expertise in both organic synthesis and polymer chemistry. Some ongoing research foci are described below:
1. Enhancing Mechanical Integrity Through Molecular Design
- Cyclic Polymers: Polymers without chain ends have a lower bulk viscosity, increased toughness, and enhanced mechanical durability compared to their conventional linear counterparts. Our group designs new initiators to synthesize cyclic polymers using ring-expansion metathesis polymerization (REMP). We then use knowledge gained from mechanistic studies with these organometallic complexes to design new classes of cyclic materials. We envision using molecular topology as the basis for creating new resins, gels, and thermosets with superior performance than their conventional counterparts.
Representative Recent Publication: Concentration Driven Ring Expansion Metathesis Polymerization via Tunable Ring Transfer Processes
- Macromolecular Shapeshifters: We exploit the dynamic “shapeshifting” ability of bullvalene and related fluxional molecules as force-responsive motifs in soft materials. Our group synthesizes these molecular cages and incorporates them into engineered thermoplastics/thermosets for specific applications in energy absorption performance materials and tough polymer glasses.
Representative Recent Publication: Molecular Ball Joints: Mechanochemical Perturbation of Bullvalene Hardy-Cope Rearrangements in Polymer Networks
2. Repurposing and (Re)Processing Soft Materials
- Functional and Degradable Rubbers: We target the mitigation of rubber waste though C-H amination process to generate new classes of elastomers. With an emphasis on mechanistic control and processing, we aim to strategically modify polydiene materials and access new genres of chemically circular materials. Current work is in close collaboration with Prof. Forrest Michael (UW Chemistry).
Representative Recent Publication: Crosslinking 1,4-Polybutadiene via Allylic Amination: A New Strategy for Deconstructable Rubbers
- Repurposing Soft Materials: We utilize ball mill mechanochemistry to selectively degrade or modify post-consumer plastics with minimal organic solvent usage. Ongoing work targets the “metamorphosis” of plastic feedstocks into soft materials with divergent bulk properties, including covalent adaptable networks with the potential for reprocessability, or into industrially-relevant chemical feedstocks. Our approaches span novel mechanochemical and solution-state techniques, with an emphasis on mechanistic control.
Representative Recent Publication: Tunable Dynamic Covalent Networks from Mechanochemical Depolymerization of Post-Consumer Aliphatic Polyesters
- Vitrimers: We also target new genres of reprocessable high performance engineering thermosets (e.g., epoxys) through a collaborative molecular design approach. Efforts span structure-function relationships across thermomechanical and bulk properties. Current work is in close collaboration with Prof. Aniruddh Vashisth (UW Mechanical Engineering) and Prof. Nikhil Kortakar (RPI Mechanical, Aerospace, & Nuclear Engineering).
Representative Recent Publication: Reversing Damage for Improved Compression After Impact in Vitrimer Composites
3. Mechanochemical Synthesis and Sensing
- Synthetic Mechanochemistry: The production of commodity and niche thermoplastics alike are synthesized more sustainably through mechanochemical methods. We use ball mill mechanochemistry, including mechanoredox catalysis, to overcome issues in building block solubility while also reducing bulk organic solvent usage. This technology enables access to block co-polymers comprised of highly immiscible monomers for self-assembly applications spanning batteries to membranes.
Representative Recent Publication: Pushing the Limits of Mechanoredox RAFT Polymerization Methods
- Mechanochemical Sensing: We harness the fluxional nature of bullvalene and related shape-shifting molecules to mechanochemically perturb macromolecular systems “out of equilibrium”. The pathway traveled on the return back to equilibrium is highly dependent on local environment, giving rise to unique spectroscopic signatures. By mechanochemically “taming” pericyclic rearrangements, we gain insight to molecular surroundings.
Representative Recent Publication: Mechanical Taming of Hardy-Cope Rearrangements
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Want to be part of our research team?
Are you a highly motivated, enthusiastic, and creative individual who wants to work on interdisciplinary projects spanning organic synthesis and polymer chemistry? Do you want the opportunity to interface cross-disciplinary with engineers and materials scientists?