More Like this

1. Efficient Computation of Single‐Chain Partition Functions in Field‐Theoretic Simulations of Polymers With Nested Tree‐Like Topologies

   https://doi.org/10.1002/mats.202500023  

   Li, Charles; Delaney, Kris T; Shell, M Scott; Fredrickson, Glenn H (July 2025, Macromolecular Theory and Simulations)

   Abstract A general algorithm is introduced to compute single‐chain partition functions in field‐theoretic simulations of polymers with nested tree‐like topologies, including self‐consistent field theory simulations that invoke the mean‐field approximation. The algorithm is an extension of a method used in a number of recent studies on the phase behavior of bottlebrush block copolymers. In those studies, the computational cost of computing single‐chain partition functions is reduced by aggregating the statistical weight of degenerate side arms. By extending this method to chains with arbitrary degrees of branching, the computational cost is reduced to scale with the total length of unique segments in the chain instead of the total length/mass of the entire chain. The method is first validated on a model dendrimer system by comparing results to coarse‐grained molecular dynamics simulations and also demonstrate its advantage over more conventional approaches to compute single‐chain partition functions. The algorithm is subsequently used to analyze the phase behavior of a molecularly informed field‐theoretic model of poly(butyl acrylate)‐graft‐poly(dodecyl acrylate) (pBA‐graft‐pDDA) copolymers in a dodecane solvent. The methodology can help advance field‐theoretic investigations of branched polymers by leveraging degeneracy in the chain to reduce computational cost and avoid the need to develop architecture‐specific algorithms. 

   more » « less
2. Enhancing photoluminescence of conjugated nanoparticles through graft polymer architectures

   https://doi.org/10.1039/D3MA00165B  

   Masucci, Ashley E.; Ghasemi, Masoud; Pester, Christian W.; Gomez, Enrique D. (June 2023, Materials Advances)

   Polymer nanoparticles are an emerging class of materials with potential impact in sensing, catalysis, imaging, cosmetics, and therapeutics. Here, a collection of graft polymers with conjugated polythiophene backbones were synthesized via a grafting-to approach. We functionalized polythiophene backbones with side chains of either poly(3-hexylthiophene) (P3HT), poly(ethylene oxide), or poly(methyl methacrylate) (PMMA) via copper-catalyzed azide–alkyne click chemistry. The backbones, graft polymers and a linear poly(3-hexylthiophene) were fabricated into nanoparticles through precipitation in aqueous media. We measured the absorption and emission spectra of the polymers dissolved in chloroform and as nanoparticles suspended in water. Compared to linear P3HT, all graft polymer nanoparticles exhibit higher quantum yields. Moreover, the addition of PMMA side chains increased the quantum yield by more than two orders of magnitude. This versatile approach to conjugated graft copolymer synthesis demonstrates a route for enhancing photoluminescence of conjugated polymer nanoparticles that could be beneficial for a variety of applications, such as biosensing and bioimaging. 

   more » « less
3. Thiol-triggered deconstruction of bifunctional silyl ether terpolymers via an S _N Ar-triggered cascade

   https://doi.org/10.1039/D3SC02868B  

   Brown, Christopher M.; Husted, Keith E.; Wang, Yuyan; Kilgallon, Landon J.; Shieh, Peyton; Zafar, Hadiqa; Lundberg, David J.; Johnson, Jeremiah A. (August 2023, Chemical Science)

   While Si-containing polymers can often be deconstructed using chemical triggers such as fluoride, acids, and bases, they are resistant to cleavage by mild reagents such as biological nucleophiles, thus limiting their end-of-life options and potential environmental degradability. Here, using ring-opening metathesis polymerization, we synthesize terpolymers of (1) a “functional” monomer ( e.g. , a polyethylene glycol macromonomer or dicyclopentadiene); (2) a monomer containing an electrophilic pentafluorophenyl (PFP) substituent; and (3) a cleavable monomer based on a bifunctional silyl ether . Exposing these polymers to thiols under basic conditions triggers a cascade of nucleophilic aromatic substitution (S N Ar) at the PFP groups, which liberates fluoride ions, followed by cleavage of the backbone Si–O bonds, inducing polymer backbone deconstruction. This method is shown to be effective for deconstruction of polyethylene glycol (PEG) based graft terpolymers in organic or aqueous conditions as well as polydicyclopentadiene (pDCPD) thermosets, significantly expanding upon the versatility of bifunctional silyl ether based functional polymers. 

   more » « less
4. Outcomes of kidney transplantation in patients with IgA nephropathy based on induction: A UNOS data analysis

   https://doi.org/10.1111/ctr.15225  

   Aydin‐Ghormoz, Emmanuel Albert; Perlmutter, Jason; Koizumi, Naoru; Ortiz, Jorge; Faddoul, Geovani (January 2024, Clinical Transplantation)

   Abstract IntroductionIgA nephropathy (IgAN) can cause end‐stage kidney disease (ESKD). This study assesses the impact of induction and maintenance immunosuppression on IgAN recurrence, graft survival, and mortality in living and deceased donor kidney transplants (LDKT and DDKT). MethodsRetrospective analysis of the UNOS database in adults with ESKD secondary to IgAN who received kidney transplants between January 2000 and June 30, 2022. Patients with thymoglobulin (ATG), alemtuzumab, or basiliximab/daclizumab induction with calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF) with or without prednisone maintenance were analyzed. Multivariate logistic regression was performed to identify factors correlated with IgA recurrence. Multivariable Cox regression analyses were performed for clinically suspected risk factors. Kaplan Meir Analysis was utilized for overall graft survival. ResultsCompared to ATG with steroid maintenance, alemtuzumab with steroid increased the odds of IgAN recurrence in DDKTs (OR 1.90,p <.010, 95% CI [1.169–3.101]). Alemtuzumab with and without steroid increased the odds of recurrence by 52% (p = .036) and 56% (p = .005), respectively, in LDKTs. ATG without steroids was associated with less risk of IgAN recurrence (HR .665,p = .044, 95% CI [.447–.989]), graft failure (HR .758,p = .002, 95% CI [.633–.907]), and death (HR .619,p <.001, 95% CI [.490–.783]) in DDKTs. Recurrence was strongly associated with risks of graft failure in DDKTs and LDKTs and death in LDKTs. ConclusionIn patients with IgAN requiring a kidney transplant, Alemtuzumab induction correlates with increased IgAN recurrence. Relapse significantly affects graft survival and mortality. ATG without steroids is associated with the least graft loss and mortality. 

   more » « less
5. Machine learning of the architecture–property relationship in graft polymers

   https://doi.org/10.1039/D5CP01334H  

   Bigting, Kevin V; Carden, Jordan J; Nag, Shubhadeep; Lawrence, Jimmy; Su, Yen-Fang; An, Yaxin (June 2025, Physical Chemistry Chemical Physics)

   Graft polymers are promising in energy and biomedical applications. However, the diverse architectures make it challenging to establish their structure–property relationships. We systematically investigate how backbone and side-chain architectures influence four key properties: glass transition temperature (Tg), self-diffusion coefficient (D), radius of gyration (Rg), and packing density (ρ). Using molecular dynamics simulations, we analyze a dataset of 500 graft polymers with randomly positioned side chains. Tg and D exhibit decoupled relationships due to the distinct topological effects. Furthermore, we develop dense neural networks (DNNs) and convolutional neural networks (CNNs) to pave the way to polymer design with desired properties. 

   more » « less