RESEARCH INTERESTS
Driven by new synthetic capability, rational molecular design, and often pure curiosity, we are interested in the design, synthesis, and manipulation of novel organic and polymeric materials. We use a combination of organic and polymer chemistry, catalysis, and various advanced characterizations to create, control, and investigate unusual (macro)molecular structures and organic materials with tailored conformations, nanostructures, properties, and functions.
Our research combines vigorous function-driven syntheses and rigorous investigation of molecular and macroscopic properties, which advance our fundamental understanding of emerging topics in chemistry and polymer science as well as address critical technological challenges in the following themes:
Our research combines vigorous function-driven syntheses and rigorous investigation of molecular and macroscopic properties, which advance our fundamental understanding of emerging topics in chemistry and polymer science as well as address critical technological challenges in the following themes:
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1. Membrane Materials for Energy-Efficient Chemical Separations
Chemical separations are essential across numerous industries and account for ~15% of total energy consumption in the US, > 4,000 trillion Btu/year. Advancements in energy-efficient separations for gases (such as CO₂, H₂, CH₄, O₂, and N₂), petrochemicals, water, critical minerals, and active pharmaceutical ingredients, among others, are critical for enabling a more sustainable future and minimizing environmental impact. Membrane technologies can significantly reduce the energy, cost, and environmental footprint of chemical separations. We develop innovative membrane materials by tuning molecular diffusion and partitioning through chemistry designs to overcome the selectivity-permeability tradeoff. Our foray into membrane materials began with the development of efficient and versatile Catalytic Arene-Norbornene AnnuLation (CANAL) to synthesize microporous rigid ladder polymers. As the power of chemistry unfolds, the CANAL chemistry also allows us to access unusual conjugated materials containing antiaromatic cyclobutadienoids. |
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Key publications:
Microporous ladder polymers: J. Am. Chem. Soc. 2014, 136, 17434. Macromolecules 2019, 52, 6294. Science 2022, 375, 1390. Review on ladder polymer synthesis: Chem. Euro. J. 2017, 23, 14101. Novel conjugated materials: J. Am. Chem. Soc. 2017, 139, 1806. J. Am. Chem. Soc. 2017, 139, 15933. Angew. Chem. Int. Ed. 2019, 58, 2034. J. Am. Chem. Soc. 2022, 144, 12715. |
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2. Deconstructable Polymers
Polymers with built-in circularity and tailored thermomechanical properties are essential for advancing sustainability and driving future technological innovation. We discovered that cyclic enol ethers can be effective monomers or comonomers in olefin metathesis polymerizations, which overturned a long belief. The overlooked reactivities allowed us to synthesize elastomers and thermosets with tunable properties and end-of-life recyclability. We also developed "polycyclohexene" with ultrahigh molecular weight, semicrystallinity, and scalable synthesis that can be catalytically depolymerized under mild conditions. Key publications: J. Am. Chem. Soc. 2020, 142, 1186. Nat. Chem. 2022, 14, 53. J. Am. Chem. Soc. 2024, 146, 25321. Adv. Mater. 2025, 2505141. |
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3. Mechanochemistry and Mechanically Responsive Materials.
In nature, mechanical stimuli are ubiquitous and vital, underlying tactile and auditory sensation, muscle contraction, and many other physiological processes. In the synthetic world, mechanical behavior of materials is important. Their strength, durability, and performance under critical conditions directly impact suitability for structural and functional applications. However, it remains a challenge to understand and manipulate mechano-transduction and response across multiple length and time scales in synthetic materials.
We are interested in soft materials with unique mechanical behaviors. We developed various mechanophore monomers and polymechanophores that transduce mechanical stimuli into multifold drastic changes in intrinsic material properties. Fundamentally, these discoveries advanced our understanding of mechanical reactivity and mechano-transduction of molecules.
In nature, mechanical stimuli are ubiquitous and vital, underlying tactile and auditory sensation, muscle contraction, and many other physiological processes. In the synthetic world, mechanical behavior of materials is important. Their strength, durability, and performance under critical conditions directly impact suitability for structural and functional applications. However, it remains a challenge to understand and manipulate mechano-transduction and response across multiple length and time scales in synthetic materials.
We are interested in soft materials with unique mechanical behaviors. We developed various mechanophore monomers and polymechanophores that transduce mechanical stimuli into multifold drastic changes in intrinsic material properties. Fundamentally, these discoveries advanced our understanding of mechanical reactivity and mechano-transduction of molecules.
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Key publications:
Science 2017, 357, 475. J. Am. Chem. Soc. 2019, 141, 6479. Nat. Chem. 2020, 12, 302. J. Am. Chem. Soc. 2020, 142, 14619. Nat. Chem. 2021, 13, 41. J. Am. Chem. Soc. 2021, 143, 12328. J. Am. Chem. Soc. 2024, 13, 296. J. Am. Chem. Soc. 2024, 146, 32651. Review/Perspective J. Am. Chem. Soc. 2025, 147, 30529. |
Past Projects
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We undertook the first systematic investigation on ROMP of various cyclopropene derivatives, and developed a unique class of cyclopropenes that undergo exclusive single addition in their olefin metathesis, allowing sequenced single additions of monomers in living ROMP and synthesis of alternating and degradable polymers.
Key publications: J. Am. Chem. Soc. 2015, 137 , 9922; Chem 2019, 5, 2691; Angew. Chem. Int. Ed. 2019, 58, 17771; ACS Macro Lett. 2020, 9, 180. Review: Acc. Chem. Res. 2021, 54, 356. |
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Dynamic network materials with tunable mechanics and dynamics. Using chemistry to tune the time-dependent mechanical properties, we have developed hydrogel materials that capture the mechanical cue of extracellular matrix for biomedical applications.
Key publications: Adv. Mater. 2018, 30, 1705215; Biomaterials 2018, 154, 213; Adv. Mater. 2021, 2104460; ACS Macro Lett. 2022, 11, 1312. |
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We embrace the interdisciplinary, dynamic nature of our research program and closely collaborate with many research groups within and outside Stanford on various aspects of these projects.
We are grateful for funding from the following sources:
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Past funding sources
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