About

Geoffrey W. Coates is the Tisch University Professor in the Department of Chemistry and Chemical Biology at Cornell University. His teaching and research interests involve science at the interface of organic, inorganic, and materials chemistry. His research focuses on the development of new synthetic strategies for producing polymers of defined structure, with control over polymer composition, architecture, stereochemistry, and molecular weight to indirectly influence polymer properties via polymer morphology. His projects are interdisciplinary, addressing problems at the interface of organic, inorganic, organometallic, and polymer chemistry. Broader impacts of his work include the creation of benign polymers and chemical synthesis, utilization of renewable resources, and development of materials for safe and economical energy storage and conversion.

Research topics

• Chemistry
• Organic chemistry
• Polymer chemistry
• Materials science
• Chemical engineering
• Combinatorial chemistry
• Composite material
• Computer Science
• Inorganic chemistry
• Polymer science
• Nanotechnology
• Photochemistry
• Physical chemistry

Selected publications

• Bio-Inspired Copper Coordination Bonds Enable Tunable, Viscoelastic, and Cytocompatible Polyhydroxyalkanoates

  ACS Polymers Au · 2026-04-28

  articleOpen accessCorresponding

  Biomaterials for repair and regeneration of soft tissues are ideally viscoelastic and processable. One way to obtain such materials is through dynamic cross-linking. Inspired by the high abundance of histidine residues in copper metalloproteins, we synthesized PHA copolymers containing imidazole side chains. The addition of a small amount of copper(II) ions results in the formation of dynamically cross-linked materials whose properties are controlled by varying the copolymer composition and counterion identity. These materials are cytocompatible with human umbilical vein endothelial cells and exhibit promising degradation timelines. This work will inform the future use of dynamically cross-linked polyhydroxyalkanoates in soft tissue applications and provide a platform for accessing the wide range of material properties necessary for many organs in the human body.

  PublisherDOI

• C–H Insertion Functionalization of Polyolefins for Versatile Polyolefin-Polyester Compatibilization

  Journal of the American Chemical Society · 2026-01-25 · 1 citations

  articleSenior authorCorresponding

  The effective recycling of commingled plastic waste blends remains a major challenge due to the immiscibility of commonly used polymers like polyethylene terephthalate (PET) with polyolefins, including high- or low-density polyethylene (HDPE, LDPE) and isotactic polypropylene (iPP). This immiscibility causes phase separation of the polymers in the blend, compromising the mechanical properties of these mixtures. Herein, we report a versatile and robust strategy to synthesize polar-group pendant polyolefins via C–H insertion from preexisting polymers, which can subsequently act as compatibilizers for blends of PET with different polyolefins. The addition of 0.5–1.0 wt % of these functionalized polyolefins to blends of PET with HDPE, LDPE, or iPP significantly improved the elongation at break, effectively restoring their material properties. This approach can be applied to prepare a compatibilizer from postconsumer HDPE bottlecaps. The waste derived compatibilizer effectively compatibilized postconsumer PET/HDPE blends, demonstrating the versatility of this method as a low-cost, efficient, and adaptable solution for restoring PET/polyolefin blend properties.

  PublisherDOI

• Surface-Initiated Hydrogen Atom Transfer Reversible Addition–Fragmentation Chain Transfer Polymerization from Isotactic Polypropylene

  Macromolecules · 2026-05-13

  articleOpen accessCorresponding

  Functionalizing isotactic polypropylene (iPP) surfaces with polymer brushes is of interest for biomedical materials, automotive parts, filtration, and packaging applications. Existing methods to graft from iPP require multiple synthetic steps or harsh stimuli such as γ-rays to initiate polymerization. Here, we describe surface-initiated hydrogen atom transfer reversible addition–fragmentation chain transfer polymerization (SI HAT-RAFT) from iPP to initiate controlled polymerization directly from the C–H bonds of iPP using visible light as a stimulus. Using a thioxanthone-derived photocatalyst and bis(trithiocarbonate) disulfide species for catalyst turnover, we achieve thick polymer brushes using a variety of acrylic monomers. Furthermore, we grafted from commercial iPP samples, including food packaging and surgical mesh. Finally, we demonstrate improved surface properties of iPP by testing the adhesion of grafted polymer surfaces to paint and aluminum. We expect this method will be an enabling technology for preparing a wide range of iPP materials.

  PublisherDOI

• Regio- and Stereoselective Lactone Polymerization: Divergent Effect of Catalyst Modification and Monomer Structure

  ACS Catalysis · 2026-04-22

  articleOpen accessCorresponding

  Selective ring-opening polymerization (ROP) of chiral lactones enables access to biodegradable polyesters with precisely controlled microstructures. Here, combined DFT modeling and experimental validation elucidate how fine-tuning of enantiopure SalBinam aluminum catalysts (through introduction of bromine atoms and tert-butyl groups, respectively, in ortho- and para-positions) modulates regio- and stereocontrol in the ROP of methyl glycolide (MeG) and lactide (LA). Computations reveal that regioselectivity in MeG polymerization arises mainly from steric repulsion, with a small contribution from weak stabilizing C-H···Br interactions that favor ring-opening at the glycolic site, consistent with the experimentally enhanced regioselectivity for (R)-MeG. In contrast, the same steric congestion at the ligand’s ortho positions destabilizes the key transition states in rac-LA polymerization, reducing the calculated stereoselectivity. Experiments confirm the predicted loss of stereocontrol, yielding nearly atactic PLA under standard conditions. Extension of the computational framework to rac-MeG polymerization promoted by racemic catalyst identified a low-barrier, stepwise polymer chain exchange pathway that rationalizes the experimentally observed syndiotacticity of poly(lactic-co-glycolic acid).

  PublisherDOI

• Synthesis of Phenyl-Substituted Poly(3-Hydroxybutyrates) with High and Tunable Glass Transition Temperatures via Sequential Catalytic Transformations

  Journal of the American Chemical Society · 2026-01-13 · 1 citations

  articleSenior authorCorresponding

  Atactic polystyrene is a commonplace transparent thermoplastic with a high glass transition temperature (Tg ∼ 100 °C), but its nondegradable backbone leads to detrimental environmental accumulation. Poly(hydroxyalkanoates) (PHAs) have emerged as biodegradable polyester alternatives to conventional olefinic plastics, but only a few PHAs possess the high Tg values (>100 °C) characteristic of polystyrene. Herein, we report the synthesis of phenyl-substituted poly(3-hydroxybutyrates) (PhPHBs) via sequential catalytic carbonylation and zinc-mediated ring-opening polymerization (ROP). Both cis and trans isomers of α-phenyl-β-butyrolactone (α-Ph-β-BL) were synthesized and polymerized to provide 13 distinct PhPHBs of varying trans incorporation and their resulting properties were systematically studied. The PhPHBs exhibit high and tunable Tg values (104–128 °C) and high thermal stability. We anticipate this work will inform the design of future high Tg PHAs as degradable alternatives to polystyrene.

  PublisherDOI

• Introduction: The Future of Plastics Sustainability

  Chemical Reviews · 2025-02-12 · 32 citations

  reviewOpen accessSenior author
  PublisherOA PDFDOI

• The Role of Intimate Dipole Carbonyl–Carbonyl and Hydrogen–Carbonyl Interactions in the Stereocomplexation and Crystallization: The Case of Poly(Cyclohexene Carbonate)

  Angewandte Chemie International Edition · 2025-10-11

  articleOpen access

  Abstract Enantiopure isotactic poly(cyclohexene carbonate) (PCHC) has been synthesized with chiral Zn‐β‐diiminate catalyst. PCHC crystallizes both as enantiopure polymer ( R )‐PCHC and ( S )‐PCHC and upon stereocomplexation of the two enantiomers. We report the crystal structures of the enantiopure polymer and of the stereocomplex ( R / S )‐PCHC and explain their crystallization based on the establishment of multiple attractive H‐‐‐O═C interactions between oxygen atoms of carbonyl groups and the hydrogen atoms of the cyclohexyl rings and C═O‐‐‐C═O intimate dipole interactions between carbonyl groups of chains of opposite chirality in the stereocomplex. The crystal structure of the enantiopure polymer is characterized by chains in 2/1 helical conformation packed in the orthorhombic unit cell with axes a = 11.55 Å , b = 9.42 Å, and c = 7.36 Å, according to the space group P 2 1 2 1 2 1 , with steric interdigitation between chains of similar chirality favored by multiple attractive H‐‐‐O═C interactions. The stereocomplex crystallizes in an orthorhombic unit cell with axes a = 10.40 Å, b = 8.41 Å, and c = 7.36 Å, according to the space group Pbc 2 1 , driven by establishment of additional C═O‐‐‐C═O dipole interactions between carbonyl groups of chains of opposite chirality, besides of the multiple attractive H‐‐‐O═C interactions.

  PublisherOA PDFDOI

• One-Step Radical-Induced Synthesis of Graft Copolymers for Effective Compatibilization of Polyethylene and Polypropylene

  ChemRxiv · 2025-05-12 · 1 citations

  preprintOpen accessSenior author

  The synthesis of copolymers from high-density polyethylene (HDPE) and isotactic polypropylene (iPP) has gained increasing attention due to its ability to improve recycling of incompatible mixed polyolefin waste feed streams. Herein, we report a new radical grafting process that yields HDPE-g-iPP copolymers from HDPE and iPP using a commercially available peroxide. Tensile testing of brittle 70/30 HDPE/iPP mixtures with these graft copolymers added showed promising compatibilization, improving the elongation at break of the blends from 20% up to 1080%. Detailed kinetic studies coupled with thermal and rheological characterization revealed optimized conditions for HDPE and iPP macroradical coupling and a deeper understanding of the grafting reaction. This optimization yielded HDPE-g-iPP copolymers that compatibilize HDPE and iPP blends at loadings as low as 2.5 wt %. The versatility of this macroradical grafting reaction was demonstrated by preparing an effective compatibilizer from untreated post-consumer waste plastics.

  PublisherOA PDFDOI

• Designing Polymers with Molecular Weight Distribution-Based Machine Learning

  Journal of the American Chemical Society · 2025-03-14 · 13 citations

  articleCorresponding

  Commodity plastics such as high density polyethylene (HDPE) have become integral to society. However, the potentially long-lasting ecological impacts of these plastics have spurred researchers to search for more sustainable solutions. One such solution is to develop a method for designing plastics with tunable and improved properties, thus decreasing the amount of material needed for various applications. In this work, we report a machine learning approach that maps the relationship between polymer molecular weight distributions (MWDs) and the physical properties (tensile and rheological) of HDPE. Using this approach, we design and generate HDPE materials with user-specified properties and valorize degraded postconsumer polyethylene waste. Implementation and development of this approach will facilitate the design of next-generation commodity materials and enable more efficient polymer recycling, thereby lowering the overall impact of HDPE on the environment.

  PublisherDOI

• Main-Chain Ketone Installation in Polyethylene Chains: A Metal-Free Strategy toward Photodegradable Plastics

  Journal of the American Chemical Society · 2025-10-02 · 8 citations

  articleSenior authorCorresponding

  Polyethylene with in-chain isolated ketones is an attractive target for achieving photodegradability while maintaining polyolefin material properties. This work reports a method to functionalize post-consumer polyethylene through radical C-H activation to install TEMPO functionalities and subsequent oxidation to obtain in-chain isolated ketones without compromising the polymer molecular weights. This process does not require metals, catalysts, or expensive reagents and allows tunable ketone incorporation up to 3 mol %. The thermal and mechanical properties were investigated to demonstrate that the ketone-containing polyethylene could potentially work as a photodegradable alternative of existing polyethylene. Photodegradation of the ketone-containing polyethylene reveals a clear decrease in molecular weights and suggests random installation of functionalities. This approach enables the conversion of post-consumer polyethylene into ketone functionalized materials through simple chemical transformations.

  PublisherDOI

Recent grants

• Bimetallic Catalysts for the Synthesis of Environmentally Benign Polymers

  NSF · $511k · 2011–2014

• DMREF: Collaborative Research: Next-Generation Nanostructured Polymer Electrolytes by Molecular Design

  NSF · $400k · 2013–2017

• FRG: GOALI: Collaborative Research: The Role of Polymer Molecular Architecture in Controlling Morphology in Quiescent and Flow-Induced Crystallization

  NSF · $320k · 2007–2012

• Development of Metal-Based Catalysts for the Synthesis of Polymers with Reduced Environmental Impact

  NSF · $680k · 2003–2009

• Development of New Catalysts for the Synthesis of Biodegradable Polymers

  NSF · $491k · 2008–2012

Frequent coauthors

• Emil B. Lobkovsky

  168 shared

• Anne M. LaPointe

  Cornell University

  58 shared

• Nitash P. Balsara

  Lawrence Berkeley National Laboratory

  54 shared

• Kiranmai Nayani

  Academy of Scientific and Innovative Research

  49 shared

• Feriel Rekhroukh

  Imperial College London

  49 shared

• Hiroto Yoshida

  Toho University

  49 shared

• Yutaro Tomisaka

  Imperial College London

  49 shared

• Syn Lett

  Indian Institute of Technology Bombay

  49 shared

Awards & honors

• The Benjamin Franklin Medal in Chemistry, The Franklin Insti…
• ACS Award in Polymer Chemistry, American Chemical Society (2…
• Alan G. MacDiarmid Medal, Department of Chemistry, Universit…
• Mislow Medal, Department of Chemistry, Princeton University…
• National Academy of Sciences Award for the Industrial Applic…