Topologically Induced Heterogeneity in Gradient Copolymer Brush Particle Materials
Abstract
A facile synthetic route toward silica brush particles with random and gradient copolymer grafts comprised of n -butyl acrylate (BA) and methyl methacrylate (MMA) using surface-initiated atom transfer radical polymerization (SI-ATRP) was developed. The effect of chain architecture on the structure and thermomechanical properties of copolymer-tethered brush particle films was investigated and compared to linear copolymer analogues. Random copolymer brush systems displayed a uniform and narrow glass transition, and the dependence of the glass-transition temperature followed a similar trend as for linear copolymers. In contrast, gradient brush materials featured a splitting of the glass-transition temperature with increasing MMA content along with a step-like increase of Young’s modulus and a decrease in ductility. The results were interpreted in terms of the effect of brush architecture on the microstructure of films. The results suggested a “molecularly uniform” microstructure in films of the random brush as well as linear random and linear gradient copolymer systems. In contrast, gradient brush systems featured a heterogeneous microstructure in which MMA-rich regions acted as “traps” that reduced chain mobility. The formation of compositional heterogeneity was rationalized by the “prescribed orientation” of gradient copolymer chains near the particle interface that amplified composition fluctuations and hence local segregation of repeat units. The results highlight the need for a better understanding of the role of “geometric constraints” on the physical properties of copolymer brush particle-based hybrid materials and the opportunity for multiple property enhancement by control of segment distribution in addition to the overall composition.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Topological heterogeneity nanoparticles offer advantages for drug delivery in cancer therapy, allowing precise control over drug loading, release kinetics, and targeting efficiency.
“The topological heterogeneity nanoparticles offer several advantages for drug delivery in cancer therapy. It allows for precise control over drug loading, release kinetics, and targeting efficiency.131”
From Smart nanoparticles for cancer therapy (2023) · cites this paper as [131]
Cites
Nanocarriers as an emerging platform for cancer therapy
Peer, D., Karp, J. M., Hong, S., Farokhzad, O. C., Margalit, R., & Langer, R. (2007) · Nature Nanotechnology · doi:10.1038/nnano.2007.387 · Cited by 8,710 · see citing works
Fox, T., & Flory, P. J. (1950) · Journal of Applied Physics · doi:10.1063/1.1699711 · Cited by 2,427 · see citing works
Polymer/Silica Nanocomposites: Preparation, Characterization, Properties, and Applications
Zou, H. H., Wu, S., & Shen, J. (2008) · Chemical Reviews · doi:10.1021/cr068035q · Cited by 2,123 · see citing works
Barbey, R., Lavanant, L., Paripovic, D., Schüwer, N., Sugnaux, C., Tugulu, S., & Klok, H.-A. (2009) · Chemical Reviews · doi:10.1021/cr900045a · Cited by 1,753 · see citing works
Self-healing polymeric materials
Yang, Y., & Urban, M. W. (2013) · Chemical Society Reviews · doi:10.1039/c3cs60109a · Cited by 1,448 · see citing works
Wang, S., & Urban, M. W. (2020) · Nature Reviews Materials · doi:10.1038/s41578-020-0202-4 · Cited by 1,410 · see citing works
Nanostructured functional materials prepared by atom transfer radical polymerization
Matyjaszewski, K. A., & Tsarevsky, N. V. (2009) · Nature Chemistry · doi:10.1038/nchem.257 · Cited by 1,256 · see citing works
Self-citationMacromolecular Engineering by Atom Transfer Radical Polymerization
Matyjaszewski, K. A., & Tsarevsky, N. V. (2014) · Journal of the American Chemical Society · doi:10.1021/ja408069v · Cited by 1,163 · see citing works
Self-citationSelf-directed self-assembly of nanoparticle/copolymer mixtures
Lin, Y., Böker, A., He, J., Sill, K., Xiang, H., Abetz, C., Li, X., Wang, J., Emrick, T. S., Long, S., et al. (2005) · Nature · doi:10.1038/nature03310 · Cited by 931 · see citing works
Current issues in research on structure–property relationships in polymer nanocomposites
Jancar, J., Douglas, J. F., Starr, F. W., Kumar, S. K., Cassagnau, P., Lesser, A. J., Sternstein, S. S., & Buehler, M. J. (2010) · Polymer · doi:10.1016/j.polymer.2010.04.074 · Cited by 925 · see citing works
High Energy Density Nanocomposites Based on Surface-Modified BaTiO 3 and a Ferroelectric Polymer
Kim, P., Doss, N. M., Tillotson, J. P., et al. (2009) · ACS Nano · doi:10.1021/nn9006412 · Cited by 818 · see citing works
Nanocomposites with Polymer Grafted Nanoparticles
Kumar, S. K., Jouault, N., Benicewicz, B. C., & Neely, T. (2013) · Macromolecules · doi:10.1021/ma4001385 · Cited by 773 · see citing works
50th Anniversary Perspective : Are Polymer Nanocomposites Practical for Applications?
Kumar, S. K., Benicewicz, B. C., Vaia, R. A., et al. (2017) · Macromolecules · doi:10.1021/acs.macromol.6b02330 · Cited by 629 · see citing works
Nanocomposites: Structure, Phase Behavior, and Properties
Kumar, S. K., & Krishnamoorti, R. (2010) · Annual Review of Chemical and Biomolecular Engineering · doi:10.1146/annurev-chembioeng-073009-100856 · Cited by 512 · see citing works
Polymer Nanocomposites with Prescribed Morphology: Going beyond Nanoparticle-Filled Polymers
Vaia, R. A., & Maguire, J. F. (2007) · Chemistry of Materials · doi:10.1021/cm062693+ · Cited by 481 · see citing works
Hui, C. M., Pietrasik, J., Schmitt, M., Mahoney, C., Choi, J., Bockstaller, M. R., & Matyjaszewski, K. A. (2013) · Chemistry of Materials · doi:10.1021/cm4023634 · Cited by 367 · see citing works
Self-citationStatistical, Gradient, Block, and Graft Copolymers by Controlled/Living Radical Polymerizations
Davis, K. A., & Matyjaszewski, K. (2007) · Springer eBooks · doi:10.1007/3-540-45806-9_1 · Cited by 325 · see citing works
Self-citationTethered Nano Building Blocks: Toward a Conceptual Framework for Nanoparticle Self-Assembly
Zhang, Horsch, M. A., Lamm, M. H., & Glotzer, S. C. (2003) · Nano Letters · doi:10.1021/nl034454g · Cited by 319 · see citing works
TiO2 nanocomposites with high refractive index and transparency
Tao, P., Li, Y., Rungta, A., et al. (2011) · Journal of Materials Chemistry · doi:10.1039/c1jm13093e · Cited by 304 · see citing works
Polymer brushes at curved surfaces
Wijmans, C. M., & Zhulina, E. B. (1993) · Macromolecules · doi:10.1021/ma00078a016 · Cited by 288 · see citing works
Belfield, K. D., Schafer, K. J., Liu, Y., Liu, J., Ren, X., & Stryland, E. W. V. (2000) · Journal of Physical Organic Chemistry · doi:10.1002/1099-1395(200012)13:12 · Cited by 272 · see citing works
Block copolymer–nanoparticle composites: Structure, functional properties, and processing
Sarkar, B., & Alexandridis, P. (2014) · Progress in Polymer Science · doi:10.1016/j.progpolymsci.2014.10.009 · Cited by 245 · see citing works
Roos, S. G., Müller, A. H. E., & Matyjaszewski, K. A. (1999) · Macromolecules · doi:10.1021/ma9819337 · Cited by 221 · see citing works
Self-citationZhen, Z., Tang, W., Wang, M., Zhou, S., Wang, H., Wu, Z., Hao, Z., Li, Z., Liu, L., & Xie, J. (2016) · Nano Letters · doi:10.1021/acs.nanolett.6b04150 · Cited by 218 · see citing works
Mechanical Reinforcement in Polymer Melts Filled with Polymer Grafted Nanoparticles
Moll, J., Akcora, P., Rungta, A., Gong, S., Colby, R. H., Benicewicz, B. C., & Kumar, S. K. (2011) · Macromolecules · doi:10.1021/ma201200m · Cited by 216 · see citing works
Yan, J., Bockstaller, M. R., & Matyjaszewski, K. A. (2019) · Progress in Polymer Science · doi:10.1016/j.progpolymsci.2019.101180 · Cited by 208 · see citing works
Self-citationKim, J., Mok, M. M., Sandoval, R. W., et al. (2006) · Macromolecules · doi:10.1021/ma061241f · Cited by 205 · see citing works
Fernandes, N. J., Koerner, H., Giannelis, E. P., et al. (2013) · MRS Communications · doi:10.1557/mrc.2013.9 · Cited by 200 · see citing works
Choi, J., Hui, C. M., Pietrasik, J., et al. (2012) · Soft Matter · doi:10.1039/c2sm06915f · Cited by 193 · see citing works
Thermosensitive Nanostructures Comprising Gold Nanoparticles Grafted with Block Copolymers
Li, D., Cui, Y., Wang, K., He, Q. Z., Yan, X., & Li, J. (2007) · Advanced Functional Materials · doi:10.1002/adfm.200700427 · Cited by 179 · see citing works
Podsiadlo, P., Krylova, G. V., Lee, B., et al. (2010) · Journal of the American Chemical Society · doi:10.1021/ja100464a · Cited by 175 · see citing works
Dispersion of polymer-grafted magnetic nanoparticles in homopolymers and block copolymers
Chen, X., Ohno, K., Ladmiral, V., & Composto, R. J. (2008) · Polymer · doi:10.1016/j.polymer.2008.05.040 · Cited by 174 · see citing works
Assemblies of Titanium Dioxide-Polystyrene Hybrid Nanoparticles for Dielectric Applications
Tchoul, M., Fillery, S. P., Koerner, H., et al. (2010) · Chemistry of Materials · doi:10.1021/cm903182n · Cited by 173 · see citing works
Encapsulation and Stabilization of Gold Nanoparticles with “Click” Polyethyleneglycol Dendrimers
Boisselier, É., Diallo, A. K., Salmon, L., Ornelas, C., Ruiz, J., & Astruc, D. (2010) · Journal of the American Chemical Society · doi:10.1021/ja909133f · Cited by 172 · see citing works
Flexible Particle Array Structures by Controlling Polymer Graft Architecture
Choi, J., Dong, H., Matyjaszewski, K. A., & Bockstaller, M. R. (2010) · Journal of the American Chemical Society · doi:10.1021/ja105189s · Cited by 145 · see citing works
Self-citationMok, M. M., Kim, J., & Torkelson, J. M. (2007) · Journal of Polymer Science Part B Polymer Physics · doi:10.1002/polb.21341 · Cited by 134 · see citing works
Grafting polystyrene onto silica nanoparticles via RAFT polymerization
Liu, C., & Pan, C. (2007) · Polymer · doi:10.1016/j.polymer.2007.04.055 · Cited by 129 · see citing works
Williams, G. A., Ishige, R., Cromwell, O. R., et al. (2015) · Advanced Materials · doi:10.1002/adma.201500927 · Cited by 127 · see citing works
Polymers on nanoparticles: structure & dynamics
Hore, M. J. A. (2019) · Soft Matter · doi:10.1039/c8sm02110d · Cited by 122 · see citing works
Structure of Polymer-Grafted Nanoparticle Melts
Midya, J., Rubinstein, M., Kumar, S. K., & Nikoubashman, A. (2020) · ACS Nano · doi:10.1021/acsnano.0c06134 · Cited by 121 · see citing works
A new class of tunable hypersonic phononic crystals based on polymer-tethered colloids
Alonso-Redondo, E., Schmitt, M., Urbach, Z. J., et al. (2015) · Nature Communications · doi:10.1038/ncomms9309 · Cited by 119 · see citing works
Surface-Initiated Polymerization I
Jordan, R. (2006) · Advances in polymer science · doi:10.1007/11569084 · Cited by 110 · see citing works
Bioinspired polymers for lubrication and wear resistance
Adibnia, V., Mirbagheri, M., Faivre, J., Robert, J., Jeungjun, L., Matyjaszewski, K. A., Lee, D. W., & Banquy, X. (2020) · Progress in Polymer Science · doi:10.1016/j.progpolymsci.2020.101298 · Cited by 96 · see citing works
Self-citationTuning Selectivities in Gas Separation Membranes Based on Polymer-Grafted Nanoparticles
Bilchak, C. R., Jhalaria, M., Huang, Y., et al. (2020) · ACS Nano · doi:10.1021/acsnano.0c07049 · Cited by 96 · see citing works
pH and Thermal Dual-Responsive Nanoparticles for Controlled Drug Delivery with High Loading Content
Zheng, Y., Wang, L., Lü, L., Wang, Q., & Benicewicz, B. C. (2017) · ACS Omega · doi:10.1021/acsomega.7b00367 · Cited by 88 · see citing works
Hore, M. J. A., Ford, J., Ohno, K., et al. (2013) · Macromolecules · doi:10.1021/ma401975a · Cited by 84 · see citing works
Polymer Structure and Conformation Alter the Antigenicity of Virus-like Particle–Polymer Conjugates
Lee, P. W., Isarov, S. A., Wallat, J. D., Molugu, S. K., Shukla, S., Sun, J., Zhang, J., Zheng, Y., Dougherty, M. L., Konkolewicz, D., et al. (2017) · Journal of the American Chemical Society · doi:10.1021/jacs.6b11643 · Cited by 80 · see citing works
The Mechanical Properties of Epoxy Composites Filled with Rubbery Copolymer Grafted SiO2
Gao, J., Li, J., Benicewicz, B. C., et al. (2012) · Polymers · doi:10.3390/polym4010187 · Cited by 77 · see citing works
Preparation and properties of biocompatible polymer-grafted silica nanoparticle
Yokoyama, R., Suzuki, S., Shirai, K., et al. (2006) · European Polymer Journal · doi:10.1016/j.eurpolymj.2006.08.015 · Cited by 75 · see citing works
Synthesis and Functionalization of ROMP-Based Gradient Copolymers of 5-Substituted Norbornenes
Dettmer, C. M., Gray, M. K., Torkelson, J. M., et al. (2004) · Macromolecules · doi:10.1021/ma036002w · Cited by 63 · see citing works
Thiophene Polymer-Grafted Barium Titanate Nanoparticles toward Nanodielectric Composites
Qiao, Y., Islam, M. S., Wang, L., et al. (2014) · Chemistry of Materials · doi:10.1021/cm502341n · Cited by 62 · see citing works
Lenart, W. R., & Hore, M. J. A. (2017) · Nano-Structures & Nano-Objects · doi:10.1016/j.nanoso.2017.11.005 · Cited by 61 · see citing works
Compatibilizing Immiscible Polymer Blends with Sparsely Grafted Nanoparticles
Alkhodairi, H., Russell, S. T., Pribyl, J. G., et al. (2020) · Macromolecules · doi:10.1021/acs.macromol.0c02108 · Cited by 61 · see citing works
Deformation Behavior of Polystyrene-Grafted Nanoparticle Assemblies with Low Grafting Density
Jiao, Y., Tibbits, A., Gillman, A. S., Hsiao, M.-S., Buskohl, P. R., Drummy, L. F., & Vaia, R. A. (2018) · Macromolecules · doi:10.1021/acs.macromol.8b01524 · Cited by 60 · see citing works
Structure and Entanglement Network of Model Polymer-Grafted Nanoparticle Monolayers
Ethier, J. G., & Hall, L. M. (2018) · Macromolecules · doi:10.1021/acs.macromol.8b01373 · Cited by 60 · see citing works
Schmitt, M., Choi, J., Hui, C. M., et al. (2016) · Soft Matter · doi:10.1039/c6sm00095a · Cited by 59 · see citing works
Materials by Design for Stiff and Tough Hairy Nanoparticle Assemblies
Hansoge, N. K., Huang, T., Sinko, R., Xia, W., Chen, W., & Keten, S. (2018) · ACS Nano · doi:10.1021/acsnano.8b02454 · Cited by 59 · see citing works
Tanaka, K., & Matyjaszewski, K. A. (2007) · Macromolecules · doi:10.1021/ma070822h · Cited by 57 · see citing works
Self-citationWong, C. L. H., Kim, J., Roth, C. B., et al. (2007) · Macromolecules · doi:10.1021/ma071187i · Cited by 57 · see citing works
Understanding Ligand Distributions in Modified Particle and Particlelike Systems
Hakem, I. F., Leech, A. M., Johnson, J. D., et al. (2010) · Journal of the American Chemical Society · doi:10.1021/ja107139c · Cited by 54 · see citing works
Cloître, M., & Besseling, R. (2010) · Advances in polymer science · doi:10.1007/978-3-642-16382-1 · Cited by 48 · see citing works
Matrix-Free Polymer Nanocomposite Thermoplastic Elastomers
Huang, Y., Zheng, Y., Sarkar, A., Xu, Y., Stefik, M., & Benicewicz, B. C. (2017) · Macromolecules · doi:10.1021/acs.macromol.7b00873 · Cited by 48 · see citing works
Voudouris, P., Choi, J., Dong, H., Bockstaller, M. R., Matyjaszewski, K. A., & Fytas, G. (2009) · Macromolecules · doi:10.1021/ma802878r · Cited by 46 · see citing works
Self-citationCollagen and collagen mimetic peptide conjugates in polymer science
He, L., & Théato, P. (2013) · European Polymer Journal · doi:10.1016/j.eurpolymj.2013.05.033 · Cited by 45 · see citing works
Fernández‐de‐Alba, C., Jimenez, A. M., Abbasi, M., et al. (2021) · Macromolecules · doi:10.1021/acs.macromol.1c01135 · Cited by 45 · see citing works
Molecular Parameters Governing the Elastic Properties of Brush Particle Films
Lee, J., Wang, Z., Zhang, J., et al. (2020) · Macromolecules · doi:10.1021/acs.macromol.9b01809 · Cited by 44 · see citing works
Self-citationReinforcement of polychloroprene by grafted silica nanoparticles
Abbas, Z. M., Tawfilas, M., Khani, M. M., Golian, K., Marsh, Z. M., Jhalaria, M., Simonutti, R., Stefik, M., Kumar, S. K., & Benicewicz, B. C. (2019) · Polymer · doi:10.1016/j.polymer.2019.03.031 · Cited by 39 · see citing works
Effect of Brush Polydispersity on the Interphase between End-Grafted Brushes and Polymeric Matrixes
Laub, C. F., & Koberstein, J. T. (1994) · Macromolecules · doi:10.1021/ma00096a025 · Cited by 37 · see citing works
Cheng, C.-H., Masuda, S., Nozaki, S., et al. (2020) · Macromolecules · doi:10.1021/acs.macromol.9b02031 · Cited by 36 · see citing works
High-Frequency Mechanical Behavior of Pure Polymer-Grafted Nanoparticle Constructs
Bilchak, C. R., Huang, Y., Benicewicz, B. C., et al. (2019) · ACS Macro Letters · doi:10.1021/acsmacrolett.8b00981 · Cited by 34 · see citing works
Sosnowski, S., Szymański, R., Lorandi, F., et al. (2021) · Macromolecules · doi:10.1021/acs.macromol.1c01930 · Cited by 28 · see citing works
Enhancing thermal transport in nanocomposites by polymer-graft modification of particle fillers
Mahoney, C., Hui, C. M., Majumdar, S., et al. (2016) · Polymer · doi:10.1016/j.polymer.2016.04.014 · Cited by 27 · see citing works
Synthesis of Gradient Copolymer Grafted Particle Brushes by ATRP
Wang, Z., Liu, T., Zhao, Y., et al. (2019) · Macromolecules · doi:10.1021/acs.macromol.9b02157 · Cited by 27 · see citing works
Self-citationControlling toughness of polymer-grafted nanoparticle composites for impact mitigation
Chen, S. H., Souna, A. J., Stranick, S. J., et al. (2021) · Soft Matter · doi:10.1039/d1sm01432c · Cited by 24 · see citing works
Data Analysis for Nanomaterials: Effective Medium Approximation, Its Limits and Implementations
Humlíček, J. (2013) · Springer eBooks · doi:10.1007/978-3-642-33956-1_3 · Cited by 23 · see citing works
Mbanga, B. L., Iyer, B. V. S., Yashin, V. V., & Balazs, A. C. (2016) · Macromolecules · doi:10.1021/acs.macromol.5b02455 · Cited by 23 · see citing works
Wang, Z., Lee, J., Wang, Z., et al. (2020) · ACS Macro Letters · doi:10.1021/acsmacrolett.0c00158 · Cited by 23 · see citing works
Self-citationDervaux, B., Junkers, T., Barner‐Kowollik, C., et al. (2009) · Macromolecular Reaction Engineering · doi:10.1002/mren.200900046 · Cited by 22 · see citing works
Polymer Spherulitic Growth Kinetics Mediated by Nanoparticle Assemblies
Altorbaq, A. S., Jimenez, A. M., Pribyl, J. G., Benicewicz, B. C., Müller, A. J., & Kumar, S. K. (2021) · Macromolecules · doi:10.1021/acs.macromol.0c02173 · Cited by 22 · see citing works
Grafted Nanoparticle Surface Wetting during Phase Separation in Polymer Nanocomposite Films
Maguire, S. M., Boyle, M. J., Bilchak, C. R., et al. (2021) · ACS Applied Materials & Interfaces · doi:10.1021/acsami.1c09233 · Cited by 20 · see citing works
Tang, S., Horton, J. M., Zhao, B., et al. (2016) · Polymer · doi:10.1016/j.polymer.2016.02.049 · Cited by 17 · see citing works
Synthesis of Ultra-high Molecular Weight SiO2-g-PMMA Particle Brushes
Wang, Z., Liu, T., Lin, K. C., et al. (2019) · Journal of Inorganic and Organometallic Polymers and Materials · doi:10.1007/s10904-019-01289-8 · Cited by 14 · see citing works
Self-citationTransparent Hybrid Opals with Unexpected Strong Resonance‐Enhanced Photothermal Energy Conversion
Cang, Y., Lee, J., Wang, Z., et al. (2020) · Advanced Materials · doi:10.1002/adma.202004732 · Cited by 14 · see citing works
Self-citationSurface and Particle Modification via RAFT Polymerization: An Update
Pribyl, J. G., & Benicewicz, B. C. (2021) · doi:10.1002/9783527821358.ch22 · Cited by 8 · see citing works
Diblock copolymer templated self-assembly of grafted nanoparticles under circular pore confinement
Gupta, S., & Chokshi, P. (2020) · Soft Matter · doi:10.1039/d0sm00124d · Cited by 7 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Smart nanoparticles for cancer therapy
Sun, L., Liu, H., Ye, Y., Lei, Y., Islam, R., Tan, S., Tong, R., Miao, Y.-B., & Cai, L. (2023) · Signal Transduction and Targeted Therapy · doi:10.1038/s41392-023-01642-x · Cited by 1,073 · see citing works
- Authors
- Zhao, Y., Wang, Z., Yu, C., Wu, H., Olszewski, M., Yin, R., Zhai, Y., Liu, T., Coronado, A., Matyjaszewski, K., & Bockstaller, M. R.
- Affiliations
- Carnegie Mellon University (US)
- Corresponding author
- Matyjaszewski, Krzysztof
- Bockstaller, Michael R.
- ORCID
- Venue
- Macromolecules
- Publisher
- American Chemical Society (ACS)
- Published
- 2022-07-28
- Volume
- 55
- Issue
- 19
- Pages
- 8846-8856
- ISSN
- 0024-9297 (ISSN-L)
- 1520-5835
- OpenAlex
- W4288428131
- Cited by
- 20
- References
- 85
- Citations by year
- 2026: 4 · 2025: 3 · 2024: 6 · 2023: 6 · 2022: 1
- FWCI
- 1.52
- Type
- journal article
- Language
- en
- Open access
- closed
- Licence
- Locations
- Macromolecules (publishedVersion)
- Funders
- Carnegie Mellon University
- Division of Civil, Mechanical and Manufacturing Innovation (CMMI-1663305)
- Division of Materials Research (DMR 1410845, DMR 2202747, DMR 2209587)
- Topics
- Physical Sciences › Chemistry › Organic Chemistry › Advanced Polymer Synthesis and Characterization
- Physical Sciences › Materials Science › Surfaces, Coatings and Films › Polymer Surface Interaction Studies
- Physical Sciences › Materials Science › Materials Chemistry › Material Dynamics and Properties
- Keywords
- butyl acrylate, methyl methacrylate, surface-initiated atom transfer radical polymerization, compositional heterogeneity, microstructure, Young's modulus, ductility, chain architecture, geometric constraints, hybrid materials
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
