About

Erin E. Stache is an Assistant Professor of Chemistry at Princeton University whose research integrates diverse fields including organic chemistry, photochemistry, inorganic materials, and polymer chemistry to advance materials science and synthesis. Her work primarily focuses on developing innovative catalytic methods to address challenges in sustainable plastics economy, such as formulating new strategies for polymerization through the discovery of novel monomers and exploring methods for recycling commercial plastics into commodity chemicals. A significant aspect of her research involves using light-to-heat conversion, known as photothermal conversion, to produce thermal gradients capable of depolymerizing plastics and promoting chemical recycling to monomers, thereby contributing to a cyclic plastic economy. Additionally, her lab investigates the application of photothermal conversion as a general strategy for organic synthesis, aiming to create complex, biologically significant compounds more efficiently. Her contributions have been recognized with awards including the NSF CAREER Award, DOE Early Career Award, and the Bayer Early Excellence in Science Award, among others.

Research topics

• Chemistry
• Photochemistry
• Polymer chemistry
• Materials science
• Organic chemistry

Selected publications

• Photothermal Conversion Promotes Challenging S _N Ar for Facile C─N Bond Formation

  Angewandte Chemie · 2026-01-19

  articleOpen accessSenior author

  Abstract Nucleophilic aromatic substitution (S N Ar) is a widely used method for forming aromatic C─N bonds, which are of interest in both industry and academia. However, current approaches are often unable to access less activated electrophiles, due to negative charge buildup in the transition state, resulting in high activation energy barriers. Inspired by our work on the Newman Kwart Rearrangement (NKR), we sought to leverage photothermal conversion for challenging C─N bond‐forming S N Ar reactions. Here, we demonstrate that the incorporation of an inexpensive photothermal agent, carbon black, and irradiation with red light affords several poorly activated intermolecular substitution reactions. Application to less activated aryl halides resulted in unproductive reactivity, leading us to examine the reaction barriers. Computations revealed barriers within the range previously achieved during our photothermally mediated NKR. Electronically neutral intramolecular analogs were synthesized and underwent productive reactivity in short time frames (≤20 min), indicating that the inhomogeneous nature of photothermal heating was a challenge in terms of colocalizing reactants sufficiently close to the particle. This concept was leveraged into a sequential S N Ar, where an initial intermolecular reaction occurs which then primes the substrate for a more difficult intramolecular substitution. This approach afforded a diverse scope of fused heterocycles.

  PublisherDOI

• Photothermal Conversion Promotes Challenging S _N Ar for Facile C─N Bond Formation

  Angewandte Chemie International Edition · 2026-01-18

  articleOpen accessSenior authorCorresponding

  Abstract Nucleophilic aromatic substitution (S N Ar) is a widely used method for forming aromatic C─N bonds, which are of interest in both industry and academia. However, current approaches are often unable to access less activated electrophiles, due to negative charge buildup in the transition state, resulting in high activation energy barriers. Inspired by our work on the Newman Kwart Rearrangement (NKR), we sought to leverage photothermal conversion for challenging C─N bond‐forming S N Ar reactions. Here, we demonstrate that the incorporation of an inexpensive photothermal agent, carbon black, and irradiation with red light affords several poorly activated intermolecular substitution reactions. Application to less activated aryl halides resulted in unproductive reactivity, leading us to examine the reaction barriers. Computations revealed barriers within the range previously achieved during our photothermally mediated NKR. Electronically neutral intramolecular analogs were synthesized and underwent productive reactivity in short time frames (≤20 min), indicating that the inhomogeneous nature of photothermal heating was a challenge in terms of colocalizing reactants sufficiently close to the particle. This concept was leveraged into a sequential S N Ar, where an initial intermolecular reaction occurs which then primes the substrate for a more difficult intramolecular substitution. This approach afforded a diverse scope of fused heterocycles.

  PublisherOA PDFDOI

• Universal Approach for the Depolymerization of Polyamides via Photothermal Conversion

  Journal of the American Chemical Society · 2026-04-23

  articleOpen accessSenior authorCorresponding

  Polyamides (PAs) exhibit excellent chemical stability and mechanical resistance, yet these same characteristics lead to their widespread accumulation in the environment as pollution. In this work, we developed an inclusive and operationally simple photothermal strategy to recycle PAs, overcoming the high energy barriers necessary to break down these materials. PAs can be depolymerized using photothermally mediated ring-closing depolymerization and acidic hydrolysis to afford cyclic and linear monomers using carbon black as a photothermal agent (PTA) under visible light irradiation. We showed that polyamide 6 is efficiently depolymerized to ε-caprolactam with 74% yield in 10 min. Similarly, in 1 h, the photothermal acidic hydrolysis of polyamide 6,6 afforded hexamethylene diamine and adipic acid with 97 and 96% yields, respectively. This method was further applied to a variety of aliphatic and aromatic PAs and mixed PA waste. Both photothermally promoted processes effectively depolymerize pigment-containing postconsumer waste by leveraging existing black pigments as PTAs. Here, photothermal conversion provided a general and rapid route for PA depolymerization under visible light irradiation, enabling high monomer yields with inexpensive reagents and a general tolerance to additives, demonstrating this approach's potential for a circular plastic economy.

  PublisherDOI

• Polyacrylate Vitrimer Network via In Situ Isocyanide Copolymerization: Synthesis and Molecular Dynamics

  Journal of the American Chemical Society · 2026-03-06 · 1 citations

  articleOpen accessSenior authorCorresponding

  Widespread plastic pollution highlights the urgent need for materials with sustainable end-of-life management. Vitrimers, cross-linked polymers containing dynamic covalent bonds, combine the durability of thermosets with their recyclability. Here, we report a one-step photocopolymerization using multifunctional isocyanides as readily accessible cross-linkers that directly introduce vinylogous urethane-like linkages into polyacrylate networks, structures difficult to obtain via amine-β-ketoester condensation. The resulting materials show good reprocessability, maintaining a comparable mechanical performance after three processing cycles. Broadband dielectric spectroscopy (BDS) reveals that the temperature dependence of the bond-exchange relaxation times evolves from a kink-like response in fresh samples to Arrhenius behavior after annealing, visualizing topological rearrangement and defect healing. A scaling relationship between bond-exchange relaxation and electrical conductivity establishes that the former is the underlying mechanism for charge transport in vitrimers. Furthermore, dipolar intermediates generated during bond exchange increase the dielectric permittivity, providing new insight into designing sustainable dielectric materials.

  PublisherDOI

• Tuning the Thermal Properties of Polymethacrylates With Bicyclobutane Monomers

  Journal of Polymer Science · 2025-04-16 · 3 citations

  articleOpen accessSenior authorCorresponding

  ABSTRACT Developing novel yet recyclable plastics is necessary as society advances and increases reliance on materials. Using new classes of monomers enables the synthesis of unprecedented polymers for new applications. Here, we report copolymerization with bicyclo[1.1.0]butane monomers to make polymers with strained backbone units and analyze the thermal property changes based on the % incorporation of strained monomers. We discover that even low incorporation (5%–20%) of methyl bicyclobutane‐1‐carboxylate (MBC) to poly(methyl methacrylate) (PMMA) increases degradation temperature while decreasing glass transition temperature. Efficient depolymerization is achieved for copolymers with 20% or fewer MBC units under photothermal conversion. Other comonomers (2‐methoxyethyl methacrylate and oligo(ethylene glycol) monomethyl ethyl methacrylate) are also copolymerized with MBC, and we assess the changes in their thermal properties, including lower critical solution temperatures (LCSTs). Our work expands the understanding of how the strained MBC monomer plays a role in copolymerization, thermal characteristics, and depolymerization of copolymers.

  PublisherOA PDFDOI

• Photothermally-driven cobalt catalysed atom transfer radical polymerisation enables isocyanide copolymer synthesis

  Polymer Chemistry · 2025-01-01 · 3 citations

  articleOpen accessSenior authorCorresponding

  A vitamin B 12 -derived photothermal catalyst enables controlled isocyanide copolymerization, synthesis of block copolymers, and temporal control via ATRP, while outperforming conventional systems under white light irradiation.

  PublisherOA PDFDOI

• Upcycling Poly(vinyl chloride) and Polystyrene Plastics Using Photothermal Conversion

  Journal of the American Chemical Society · 2025-01-13 · 44 citations

  articleSenior authorCorresponding

  Poly(vinyl chloride) (PVC) and polystyrene (PS) are among the least recycled plastics. In this work, we developed a simple and novel strategy to valorize PVC and PS plastics via photothermal conversion to (1-chloroethyl)benzene, a commodity chemical with excellent versatility. As PVC is known to release HCl gas and decompose into conjugated polyenes, we envisioned a dual role for PVC plastics. While the in situ-generated HCl serves as a chlorine source, the resulting dehydrochlorinated-PVC (DHPVC) functions as a photothermal agent to accelerate the hydrochlorination of styrene. We converted PVC and styrene in up to 89% (1-chloroethyl)benzene in less than 1 h of white light irradiation. Subsequent nucleophilic substitution on the chloro-adduct formed 1-phenylethanol (a fragrance additive) and fendiline (a heart disease drug) in high yields. The PVC photothermal hydrochlorination system is applied to various alkenes and is compatible with post-consumer waste PVC plastics and plasticizers. Ultimately, PVC upcycling with photothermally recycled styrene achieved 84% (1-chloroethyl)benzene under white LED light in 1 h, and co-upcycling of PS and PVC achieved 42% yield under focused sunlight irradiation in just 4 min.

  PublisherDOI

• Synthesis, mechanical and dielectric properties ofpoly(acrylate-co-isocyanide) vitrimers

  ChemRxiv · 2025-05-19

  preprintOpen accessSenior author

  The rampant production and persistence of plastics in the environment have underscored the urgent need for a paradigm shift towards developing and adopting new materials with their end-of-life design in mind. Vitrimers are a class of crosslinked polymers that exhibit recyclable characteristics as sustainable alternatives to thermosets due to their dynamic bonds. Here, we develop multifunctional isocyanides as readily accessible cross-linking monomers capable of directly integrating a dynamic covalent network into polyacrylate backbones. These cross-linkers offer a simple, cost-effective approach to producing vitrimers via photo copolymerization. The resulting material exhibits high cross-linking density along with reprocessability. Dynamic mechanical analysis (DMA) and broadband dielectric spectroscopy (BDS) were conducted to investigate the bond exchange kinetics and segmental dynamics of the network. Compared to non-dynamically crosslinked PMA, the introduction of dynamic bonds shows faster segmental dynamics, i.e. dynamic Tg, by BDS analysis, which accelerates further with increasing cross-linking density. Our investigation shows both bond exchange and plasticization contribute to the reduction of Tg. Additionally, the bond exchange relaxation exhibited a dual Arrhenius-like behavior, which was attributed to the rapid incorporation of free amines as the temperature increased. Finally, the high dipole moment of the dynamic bond led to the higher permittivity of the vitrimers compared to non-dynamically cross-linked PMA, demonstrating the potential of these polymers as dielectric materials.

  PublisherOA PDFDOI

• Cumene-to-Phenol Process Mediated by Bromine Radicals through Photoinduced Ligand-to-Metal Charge Transfer

  Synlett · 2025-05-16 · 1 citations

  articleSenior author

  Abstract Selective C–H activation via hydrogen atom transfer (HAT) has gained significant interest recently. One industrial application for HAT can be found in the tertiary benzylic C–H bond of cumene for producing phenol, a versatile chemical feedstock for various industries. However, the overall phenol yield remains low using the existing Hock process due to the poor selectivity towards the key reaction intermediate, cumene hydroperoxide (CHP). Here, we demonstrate an efficient strategy for phenol production through photooxidation of cumene to CHP using iron bromide under blue light irradiation, where bromine radicals (generated in situ via ligand-to-metal charge transfer) are used as hydrogen atom abstractors. Mechanistic studies revealed the cumene-to-CHP conversion occurred via a tertiary C–H bond abstraction by a radical mechanism, and the acetic acid and water additives increased CHP selectivity through stabilizing peroxides. The cumene-phenol process achieved up to 88% yield of CHP in 1 hour and could be used with a wide range of substrates. We thus developed a selective, mild, and efficient phenol production method using iron bromide under photooxidative conditions.

  PublisherDOI

• A Universal Approach for Chemical Recycling to Monomers using Photothermally Activated Hierarchically Porous Carbon

  ChemRxiv · 2025-08-14 · 2 citations

  articleSenior author

  Chemical recycling of plastics to monomers offers a promising strategy to address massive plastic waste. However, most chemical recycling methods are narrowly limited to specific polymer resins. Pyrolysis offers generality for universal polymer recycling, but energy inefficiencies and degradation products as a result of overheating make this strategy less practical. Herein, we report a photothermal depolymerization approach that is general to numerous polymers with high selectivity. We identified hierarchical porous carbon material upcycled from proteins as a high surface area photothermal agent without requiring direct incorporation into polymer resin. We successfully depolymerize a wide range of polymers, including polystyrene (PS), poly(methyl methacrylate) (PMMA), polyvinyl acetate (PVA), polyvinyl alcohol (PVOH), trans-polyisoprene, polypropylene carbonate (PPC), poly(L-lactide) (PLLA), polyethylene terephthalate (PET), and polycarbonate (PC). Additionally, the porous carbon material has extended lifetime (can be used at least 5 cycles) by sequential addition of polystyrene films to the post-reacted porous carbon materials. Excitingly, this method is broadly applicable to post-consumer plastics without preprocessing and is readily scalable, demonstrating the versatility of this closed-loop chemical recycling approach.

  PublisherDOI

Recent grants

• Photothermal Catalysis: Using light to thermally generate reactive intermediates with temporal and spatial control

  NIH · $1.2M · 2023–2028

Frequent coauthors

• Tomislav Rovis

  Columbia University

  14 shared

• Sewon Oh

  Cornell University

  11 shared

• Abigail G. Doyle

  Vanderbilt University

  11 shared

• Lejla Čamdžić

  Cornell University

  9 shared

• Brett P. Fors

  Cornell University

  8 shared

• Evandro Maia Ferreira

  6 shared

• Alyssa B. Ertel

  Princeton University

  6 shared

• Brian J. Knight

  5 shared

Labs

• Stache LabPI

Awards & honors

• Bayer Early Excellence in Science Award, Chemistry (2023)
• NSF CAREER Award (2023)
• DOE Early Career Award (2023)
• ACS Petroleum Research Fund Doctoral New Investigator Grant…
• Thieme Chemistry Journal Award (2021)