Christopher M. Bates

· Associate Professor, MaterialsVerified

University of California, Santa Barbara · Materials

Active 1984–2026

h-index37

Citations6.3k

Papers11262 last 5y

Funding$1.0M1 active

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About

Professor Christopher M. Bates leads a research group within the Materials Department at UC Santa Barbara. The Bates Group focuses on the design, synthesis, characterization, and application of new soft materials. Their work involves exploring innovative approaches to develop materials with novel properties and functionalities. The group is actively engaged in advancing the understanding and practical use of these soft materials, contributing to the broader field of materials science.

Research topics

Nanotechnology
Materials science
Chemistry
Composite material
Artificial Intelligence
Organic chemistry
Chemical engineering
Computer Science
Polymer chemistry
Engineering
Polymer science
Physics
Computational chemistry

Selected publications

Degradable Vinyl-Based Polymers by Radical Ring-Opening Polymerization: A User Guide
ACS Polymers Au · 2026-04-11
articleOpen access
Low weight, low price, and excellent long-term stability are the main advantages of vinyl-based polymers. Such polymers are obtained by chain-growth processes leading to all-carbon backbones, which are non(bio)degradable and nonchemically recyclable. Unfortunately, this chemical stability manifests as postuse persistence; coupled with poor waste management practices, polymers including vinyl derivatives pose major environmental problems today. Given that it is very difficult and costly to design entirely new materials that have both desired properties (mechanical, thermal, solvent resistance, etc.) and recyclability and/or biodegradability at the end of their life cycle, it seems worthwhile to transform already known materials into (bio)degradable/chemically recyclable equivalents. One approach is based on the introduction of cleavable bonds into the polymer backbone, so that degradation (by hydrolysis, for example) produces oligomers which can then be further recycled and/or bioassimilated by micro-organisms. An effective method for incorporating weak bonds randomly into the C–C backbone of a vinyl polymer is the copolymerization of vinyl monomers with cyclic monomers by radical ring-opening polymerization (rROP). This method combines the advantages of ring-opening and radical polymerization, i.e., the production of polymers with heteroatoms and/or functional groups in the main chain, with the robustness, ease of use, and mild polymerization conditions of a radical process. The aim of this tutorial review is to provide polymer chemists with guidelines to use rROP to prepare vinyl-based materials with predictable degradation. This review thus presents the rROP principle, the main families of cyclic monomers copolymerizable with vinyl monomers, and the main applications of the resulting (bio)degradable/chemically recyclable materials (polymers for packaging, latexes and degradable surfaces, 3D printing, biomaterials and water-soluble polymers).
Publisher DOI
Light-Induced Copolymerization of Ethyl Lipoate and Vinyl Monomers: Increased Efficiency and Degradability
Macromolecules · 2025-12-10 · 7 citations
articleCorresponding
Radical ring-opening copolymerization of lipoic acid derivatives with vinyl monomers (VMs) is a versatile route to create degradable copolymers and enables tuning of vinyl polymer properties. Although thermally initiated systems with acrylates, styrene, and acrylamide are well established, photoinduced polymerization remains comparatively underexplored. In this work, we investigate the photopolymerization of ethyl lipoate (ELp) with diverse VMs, including butyl acrylate (BA), N,N-dimethylacrylamide (DMA), methyl methacrylate (MMA), N-vinylpyrrolidone (NVP), vinyl acetate (VAc), isobutyl vinyl ether (IBVE), and norbornene (NB) under 405 nm light. We show that efficient copolymerization is obtained with the use of the photoinitiator (diphenylphosphoryl)(mesityl)methanone (TPO). In its absence, ELp undergoes photolysis to produce only low-molecular-weight oligomers (Mn = 1–2 kg mol–1) with limited monomer conversion (≤20%). In contrast, with TPO, all comonomers, except for styrene and allyl alcohol, achieve efficient polymerization, yielding high molecular weight copolymers (Mn > 19 kg mol–1). In addition, we compared the TPO initiated photopolymerization at ambient temperature with AIBN-initiated conventional thermal polymerization at 70 °C. We found that ELp exhibits significantly higher conversion under photopolymerization. Monomers such as VAc, IBVE, and NB show much better incorporation when using photoinitiated polymerization conditions, whereas methyl methacrylate and styrene are more suitable for thermal polymerization. Using VAc as a representative case, we further examine how the ELp: VAc feed ratio influences copolymerization kinetics and final copolymer composition. Finally, the resulting VM–ELp copolymers undergo thiolate-promoted disulfide exchange, with Mn values decreasing significantly from 19–82 kg mol–1 to 1–2 kg mol–1. Finally, we evaluated the thermal properties of the copolymers. The VAc-co-ELp copolymer containing 15 mol % ELp shows comparable thermal stability to the corresponding VAc homopolymer. However, TGA analysis reveals that the copolymer undergoes a more complete thermal decomposition at lower temperatures. Collectively, this work highlights a substantial, untapped potential of photoinduced lipoate–vinyl copolymerization for creating degradable and functional polymeric materials.
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Data-Efficient Methods for Determining Flory–Huggins χ Parameters in Multicomponent Polymer Formulations
Macromolecules · 2025-11-12 · 1 citations
article
Polymer formulations are essential in diverse applications including personal care products, coatings, paints, adhesives, and plastic materials. Designing these formulations requires navigating large, complex design spaces, where phase and self-assembly behavior critically impact performance. The Flory–Huggins χ parameter, which quantifies segmental miscibility, is widely used to parametrize the excess free energy of mixing in formulation models. In this work, we introduce two data-efficient, top-down methods for estimating χ parameters using the Random Phase Approximation (RPA): (i) Boundary Nonlinear Regression (Boundary-NLR), which fits theoretical spinodal boundaries to experimental phase boundaries, and (ii) Surrogate Model Inverse Parameter Estimation (SMIPE), which uses a Gaussian Process Classifier to fit sparse phase maps via a surrogate model. Both methods allow rapid parametrization of polymer field-theoretic models without the need for additional experiments. We evaluate these approaches on data sets involving polymer–solvent–nonsolvent ternary mixtures and block copolymer–solvent systems, demonstrating their robustness to experimental noise and their relevance for real-world formulation design.
Publisher DOI
Controlled Synthesis of Lipoate Homopolymers via Reversible Addition–Fragmentation Chain Transfer Polymerization
Journal of the American Chemical Society · 2025-10-06 · 8 citations
article
Polylipoates (PLp), derived from α-lipoic acid, are promising polymers for developing biocompatible, stimuli-responsive, and fully (closed-loop) recyclable materials. However, their synthesis is hindered by two key challenges: the high propensity of lipoate propagating radicals to undergo backbiting during polymerization, and the tendency for polymers to spontaneously depolymerize due to a low ceiling temperature. In this study, we demonstrate that reversible addition–fragmentation chain transfer (RAFT) polymerization overcomes these challenges and can be used to synthesize PLp homopolymers with a high degree of control. This was confirmed by a linear relationship between molecular weight (Mn) and monomer conversion, as well as first-order polymerization kinetics, characteristics not achievable with conventional radical polymerization. By adjusting the RAFT agent feed ratio, the Mn of homopolymer PLps was precisely controlled with an Mn ranging from 3.6 to 62.6 kg mol–1. RAFT polymerization provided stable end-groups that effectively suppressed the spontaneous depolymerization of PLp. Polymers synthesized using RAFT agents remained intact for over 2 weeks in both solution and bulk, while those prepared under traditional radical conditions showed substantial degradation. Moreover, the trithiocarbonate end-group enabled light-triggered, on-demand depolymerization back to the original monomer. RAFT was also successfully extended to the synthesis of degradable block copolymers. Together, these results demonstrate that RAFT offers a simple, accessible, and proven strategy to address key challenges in PLp synthesis and long-term stability.
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Rule 5: Stay Focused
2025-01-01
book-chapterSenior author
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Molecular Cross-Linking Enhances Stability of Non-Fullerene Acceptor Organic Photovoltaics
ACS Energy Letters · 2025-01-01 · 15 citations
article
Understanding efficiency–durability relationships and related mitigation strategies is an important step toward the commercialization of organic photovoltaics (OPVs). Here, we report that a photoactivated 6-bridged azide cross-linker (6Bx) improves the morphological stability by suppressing the thermally activated diffusion of (Y6) acceptor molecules in PM6:Y6 bulk-heterojunction (BHJ)-based OPVs. Cross-linked PM6:Y6 (0.05 wt % 6Bx) BHJ OPVs retain 93.4% of the initial power conversion efficiency upon thermal aging at 85 °C for 1680 h (T80 = 3290 h). Molecular origins of enhanced thermal stability are corroborated by optical spectroscopy, surface imaging, 2D solid-state nuclear magnetic resonance (ssNMR), Raman spectroscopy, scanning electron diffraction (SED) measurements, and analysis of the BHJ thin films. The facile single-step cross-linking strategy in conjugation with advanced characterization methods presented in the study paves the way toward developing durable OPVs based on non-fullerene acceptors (NFAs).
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Rule 7: Know the Impact of Geopolitical Influence on Investments
2025-01-01
book-chapterSenior author
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Rule 1: Learn How to Invest
2025-01-01
book-chapterSenior author
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Intelligent Investing in Irrational Markets
2025-01-01
bookSenior author
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Epilogue
2025-01-01
book-chapterSenior author
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