Scholarly Works, Macromolecules Innovation Institute (MII)

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Rapid Design and Fabrication of Body Conformable Surfaces with Kirigami Cutting and Machine Learning
Bali, Jyotshna; Li, Jinyang; Chen, Jie; Li, Suyi (Wiley, 2026-02-10)
By integrating the principles of kirigami cutting and data-driven modeling, this study aims to develop a personalized, rapid, and low-cost design and fabrication pipeline for creating body-conformable surfaces around the knee joint. The process begins with 3D scanning of the anterior knee surface of human subjects, followed by extracting the corresponding skin deformation between two joint angles in terms of longitudinal strain and Poisson's ratio. In parallel, a machine learning model is constructed using extensive simulation data from experimentally calibrated finite element analysis. This model employs Gaussian Process (GP) regression to relate kirigami cut lengths to the resulting longitudinal strain and Poisson's ratio. With an R² score of 0.996, GP regression outperforms other models in predicting kirigami's large deformations. Finally, an inverse design approach based on the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) is used to generate kirigami patch designs that replicate the in-plane skin deformation observed from the knee scans. This pipeline was applied to three human subjects, and the resulting kirigami knee patches were fabricated using rapid laser cutting, requiring less than a business day from knee scanning to kirigami patch delivery. The low-cost, personalized kirigami patches successfully conformed to over 75% of the skin area across all subjects. The kirigami-inspired, machine-learning-driven design and fabrication pipeline presents a balanced trade-off between conformability performance and cost for personalizing wearables, thus establishing a foundation for a wide range of new functional devices.
Analytical interaction potential for Lennard-Jones rods
Wang, Junwen; Seidel, Gary D.; Cheng, Shengfeng (American Physical Society, 2025-01-03)
An analytical form has been derived using Ostrogradsky's integration method for the interaction between two thin rods of finite lengths in arbitrary relative configurations in a three-dimensional space, each treated as a line of point particles interacting through the Lennard-Jones 12-6 potential. Simplified analytical forms for coplanar, parallel, and collinear rods are also derived. Exact expressions for the force and torque between the rods are obtained. Similar results for a point particle interacting with a thin rod are provided. These interaction potentials can be widely used for analytical descriptions and computational modeling of systems involving rodlike objects such as liquid crystals, colloids, polymers, elongated viruses and bacteria, and filamentous materials including carbon nanotubes, nanowires, biological filaments, and their bundles.
Analytical sphere-thin rod interaction potential
Wang, Junwen; Cheng, Shengfeng (Springer, 2025-05)
A compact analytical form is derived through an integration approach for the interaction between a sphere and a thin rod of finite and infinite lengths, with each object treated as a continuous medium of material points interacting by the Lennard-Jones 12-6 potential and the total interaction potential as a summation of the pairwise potential between material points on the two objects. Expressions for the resultant force and torque are obtained. Various asymptotic limits of the analytical sphere–rod potential are discussed. The integrated potential is applied to investigate the adhesion between a sphere and a thin rod. When the rod is sufficiently long and the sphere sufficiently large, the equilibrium separation between the two (defined as the distance from the center of the sphere to the axis of the rod) is found to be well approximated as a+0.787σ, where a is the radius of the sphere and σ is the unit of length of the Lennard–Jones potential. Furthermore, the adhesion between the two is found to scale with a √a.
Effect of particle shape on stratification in drying films of binary colloidal mixtures
Liu, Binghan; Grest, Gary S.; Cheng, Shengfeng (AIP Publishing, 2025-07-21)
The role of particle shape in evaporation-induced auto-stratification in polydisperse colloidal suspensions is explored with molecular dynamics simulations of mixtures of spheres and aspherical particles. A unified framework based on the competition between diffusion and diffusiophoresis is proposed to understand the effects of shape and size dispersity. In general, particles diffusing more slowly (e.g., larger particles) tend to accumulate more strongly at the evaporation front. However, larger particles have larger surface areas and therefore greater diffusiophoretic mobility. Hence, they are more likely to be driven away from the evaporation front via diffusiophoresis. For a rapidly dried bidisperse suspension containing small and large spheres, the competition leads to “small-on-top” stratification. Here, we employ a computational model in which the diffusion coefficient is inversely proportional to particle mass. For a mixture of spheres and aspherical particles with similar mass, the diffusion contrast is reduced, and the spheres are always enriched at the evaporation front as they have the smallest surface area for a given mass and, therefore, the lowest diffusiophoretic mobility. For a mixture of solid and hollow spheres that have the same outer radius and thus the same surface area, the diffusiophoretic contrast is suppressed, and the system is dominated by diffusion. Consequently, the solid spheres, which have a larger mass and diffuse more slowly, accumulate on top of the hollow spheres. Finally, for a mixture of thin disks and long rods that differ significantly in shape but have similar mass and surface area, both diffusion and diffusiophoresis contrasts are suppressed, and the mixture does not stratify.
Analytical Interaction Potentials for Disks in Two Dimensions
Liu, Binghan; Wang, Junwen; Grest, Gary S.; Cheng, Shengfeng (2025-11-25)
Compact analytical forms are derived for the interactions involving thin disks in two dimensions using an integration approach. These include interactions between a disk and a material point, between two disks, and between a disk and a wall. Each object is treated as a continuous medium of materials points interacting by the Lennard-Jones 12-6 potential. By integrating this potential in a pairwise manner, expressions for the potentials and resultant forces between extended objects are obtained. All the results are validated with numerical integrations. The analytical potentials are implemented in LAMMPS and used to simulate two-dimensional suspension of disks with an explicit solvent modeled as a Lennard-Jones liquid. In monodisperse disk suspensions, a disorderto- order transition of disk packing is observed as the area fraction of disks is increased or as the solvent evaporates. In bidisperse disk suspensions being rapidly dried, stratification is found with the smaller disks enriched at the evaporation front. Such “small-on-top” stratification echoes the similar phenomenon occurring in three-dimensional polydisperse colloidal suspensions that undergo fast drying. These potentials can be applied to a wide range of two-dimensional systems involving disk-like objects.
The need to implement FAIR principles in biomolecular simulations
Amaro, Rommie E.; Aqvist, Johan; Bahar, Ivet; Battistini, Federica; Bellaiche, Adam; Beltran, Daniel; Biggin, Philip C.; Bonomi, Massimiliano; Bowman, Gregory R.; Bryce, Richard A.; Bussi, Giovanni; Carloni, Paolo; Case, David A.; Cavalli, Andrea; Chang, Chia-En A.; Cheatham, Thomas E.; Cheung, Margaret S.; Chipot, Christophe; Chong, Lillian T.; Choudhary, Preeti; Cisneros, G. Andres; Clementi, Cecilia; Collepardo-Guevara, Rosana; Coveney, Peter; Covino, Roberto; Crawford, T. Daniel; Dal Peraro, Matteo; de Groot, Bert L.; Delemotte, Lucie; De Vivo, Marco; Essex, Jonathan W.; Fraternali, Franca; Gao, Jiali; Gelpi, Josep Ll; Gervasio, Francesco L.; Gonzalez-Nilo, Fernando D.; Grubmuller, Helmut; Guenza, Marina G.; Guzman, Horacio V.; Harris, Sarah; Head-Gordon, Teresa; Hernandez, Rigoberto; Hospital, Adam; Huang, Niu; Huang, Xuhui; Hummer, Gerhard; Iglesias-Fernandez, Javier; Jensen, Jan H.; Jha, Shantenu; Jiao, Wanting; Jorgensen, William L.; Kamerlin, Shina CL L.; Khalid, Syma; Laughton, Charles; Levitt, Michael; Limongelli, Vittorio; Lindahl, Erik; Lindorff-Larsen, Kresten; Loverde, Sharon; Lundborg, Magnus; Luo, Yun L.; Luque, F. Javier; Lynch, Charlotte I.; MacKerell, Alexander D.; Magistrato, Alessandra; Marrink, Siewert J.; Martin, Hugh; McCammon, J. Andrew; Merz, Kenneth; Moliner, Vicent; Mulholland, Adrian J.; Murad, Sohail; Naganathan, Athi N.; Nangia, Shikha; Noe, Frank; Noy, Agnes; Olah, Julianna; O'Mara, Megan L.; Ondrechen, Mary Jo; Onuchic, Jose N.; Onufriev, Alexey V.; Osuna, Silvia; Palermo, Giulia; Panchenko, Anna R.; Pantano, Sergio; Parish, Carol; Parrinello, Michele; Perez, Alberto; Perez-Acle, Tomas; Perilla, Juan R.; Pettitt, B. Montgomery; Pietropaolo, Adriana; Piquemal, Jean-Philip; Poma, Adolfo B.; Praprotnik, Matej; Ramos, Maria J.; Ren, Pengyu; Reuter, Nathalie; Roitberg, Adrian; Rosta, Edina; Rovira, Carme; Roux, Benoit; Rothlisberger, Ursula; Sanbonmatsu, Karissa Y.; Schlick, Tamar; Shaytan, Alexey K.; Simmerling, Carlos; Smith, Jeremy C.; Sugita, Yuji; Swiderek, Katarzyna; Taiji, Makoto; Tao, Peng; Tieleman, D. Peter; Tikhonova, Irina G.; Tirado-Rives, Julian; Tunon, Inaki; van der Kamp, Marc W.; van der Spoel, David; Velankar, Sameer; Voth, Gregory A.; Wade, Rebecca; Warshel, Ariel; Welborn, Valerie Vaissier; Wetmore, Stacey D.; Wheeler, Travis J.; Wong, Chung F.; Yang, Lee-Wei; Zacharias, Martin; Orozco, Modesto (Nature Portfolio, 2025-04)
In the Big Data era, a change of paradigm in the use of molecular dynamics is required. Trajectories should be stored under FAIR (findable, accessible, interoperable and reusable) requirements to favor its reuse by the community under an open science paradigm.
Is AMOEBA a Good Force Field for Molecular Dynamics Simulations of Carbohydrates?
Deegbey, Mawuli; Sumner, Ethan W.; Welborn, Valerie Vaissier (2025-05-20)
Over the years, molecular dynamics (MD) simulations have been employed in the study of carbohydrates, with force fields such as CHARMM, AMBER/GLYCAM, and GROMOS. Although these force fields have achieved considerable success and played a pivotal role in our understanding of carbohydrate chemistry, growing interest has emerged in incorporating polarization effects to enhance the accuracy of simulations. In this perspective, we contemplate the advances that have been made in nonpolarizable and polarizable force fields to extract the key factors controlling accuracy in MD of carbohydrates. We find that the extreme hydrophilicity and conformational flexibility of carbohydrates pose challenges for most force fields. Overall, a force field suited for carbohydrates needs to include a water model developed consistently with the solute parameter sets, a soft van der Waals repulsion term at short distances, and polarization (whether implicit or explicit). We find that AMOEBA improves the prediction of hydration shell structure and dynamics, hydrogen bonding, and kinetics of diffusion, although it remains largely untested for conformational flexibility and glycosidic linkages. Nevertheless, AMOEBA’s recent success in modeling monosaccharides without revisions of the potential energy functions or water model presents a promising avenue for future research. Such advances will provide deeper insights into the structure, dynamics, and interactions of these biologically and industrially relevant macromolecules.
Preorganized Electric Fields in Voltage‐Gated Sodium Channels
Zheng, Yi; Chen, Taoyi; Welborn, Valerie Vaissier (Wiley-VCH, 2025-05-27)
Enzymes are reported to catalyze reactions by generating electric fields that promote the evolution of the reaction in the active site. Although seldom used outside enzymatic catalysis, electrostatic preorganization theory and language of electric fields can be generalized to other biological macromolecules. Herein, we performed molecular dynamics simulations of human Nav1.5, Nav1.6, and Nav1.7 with the atomic multipole optmimized energetics for biomolecular applications polarizable force field. We show that in the absence of an external potential, charged and uncharged residues generate strong electric fields that assist in Naþ motion in the pore. This work emphasizes the importance of charge–dipole interactions in modulating Naþ dynamics, in addition to charge–charge interactions, the focus of a majority of previous studies. Finally, we find that residues share a high level of mutual information through electric fields that can enable the optimization of allosteric pathways.
Water Accelerates in the Hydration Shell of the N- and C-Terminal Domains of α-Synuclein in the Presence of NaCl
Koehler, Stephen J.; Welborn, Valerie Vaissier (American Chemical Society, 2026-01)
α-Synuclein (α-Syn) is an intrinsically disordered protein (IDP) whose aggregation into fibrils is implicated in Parkinson's disease (PD). While benign α-Syn aggregation frequently occurs, off-target aggregates are implicated in disease progression. Although most mechanisms of toxic α-Syn aggregate formation are unknown, high concentrations of salt ions have been shown to systematically result in faster aggregation. Previous work suggests that salt slows water in the hydration shell of α-Syn, promoting intermolecular interactions. Here, we use polarizable molecular dynamics (MD) to investigate the interactions between α-Syn and water in response to an increased NaCl concentration. While we also find that the water in the hydration shell of the nonamyloid-β component (NAC) domain slows down with increasing salt concentration, the water in the hydration shell of the N- and C-terminal domains accelerates. The segments of the N- and C-terminal domains that show faster water diffusion kinetics corroborate with truncation experiment results. Overall, our work suggests that α-Syn aggregation is related to partial salt-induced dehydration of the N- and C-terminal domains.
Tuning Polyacrylate Composition to Recognize and Modulate Fluorescent Proteins
Gomez, Darwin C.; Seth, Swarnadeep; Mondal, Ronnie; Koehler, Stephen J.; Baker, Jared G.; Plate, Charles; Anderson, Ian C.; Smith, Mikayla R.; Gloriod, Joey; Gunter, Morgan; Welborn, Valerie Vaissier; Deshmukh, Sanket A.; Figg, C. Adrian (Wiley-VCH, 2026-01-09)
Molecular definition is usually regarded as a prerequisite to achieve protein recognition and functional modulation, particularly for macromolecular interactions. Herein, we report that polymers with specific combinations of monomers arranged into random sequences [random hetero oligomers (RHOs)] can selectively bind to a model protein. Using green fluorescent protein (GFP) as a target, polyacrylates were developed that bound with nanomolar affinity and enhanced fluorescence by >100%. Purification of the polymerization product revealed subpopulations of compositions with distinct affinities and selectivity for GFP over a competing protein. Experimental and computational binding analyses confirmed that there are distinct RHO–GFP interactions, which are influenced by RHO chemical composition. These findings show that sequence-defined structures are not a prerequisite for selective protein recognition. Synthetic polymers can instead serve as scalable, tunable platforms for molecular recognition—representing a significant leap towards next-generation sensing, therapeutic, responsive, and catalytic materials in domains previously dominated by biologics or complex peptide scaffolds.
Silica-Biomacromolecule Interactions: Toward a Mechanistic Understanding of Silicification
McCutchin, Christina A.; Edgar, Kevin J.; Chen, Chun-Long; Dove, Patricia M. (American Chemical Association, 2024-10-09)
Silica-organic composites are receiving renewed attention for their versatility and environmentally benign compositions. Of particular interest is how macromolecules interact with aqueous silica to produce functional materials that confer remarkable physical properties to living organisms. This Review first examines silicification in organisms and the biomacromolecule properties proposed to modulate these reactions. We then highlight findings from silicification studies organized by major classes of biomacromolecules. Most investigations are qualitative, using disparate experimental and analytical methods and minimally characterized materials. Many findings are contradictory and, altogether, demonstrate that a consistent picture of biomacromolecule-Si interactions has not emerged. However, the collective evidence shows that functional groups, rather than molecular classes, are key to understanding macromolecule controls on mineralization. With recent advances in biopolymer chemistry, there are new opportunities for hypothesis-based studies that use quantitative experimental methods to decipher how macromolecule functional group chemistry and configuration influence thermodynamic and kinetic barriers to silicification. Harnessing the principles of silica-macromolecule interactions holds promise for biocomposites with specialized applications from biomedical and clean energy industries to other material-dependent industries.
Rechargeable Manganese Dioxide Hard Carbon Lithium Batteries in an Ether Electrolyte
Xia, Dawei; Rosenberg, Keith; Li, Yilin; Hu, Anyang; Sun, Chengjun; Li, Luxi; Nordlund, Dennis; Sainio, Sami; Huang, Haibo; Lin, Feng (Electrochemical Society, 2024-03-31)
Earth-abundant, cost-effective electrode materials are essential for sustainable rechargeable batteries and global decarbonization. Manganese dioxide (MnO2) and hard carbon both exhibit high structural and chemical tunability, making them excellent electrode candidates for batteries. Herein, we elucidate the impact of electrolytes on the cycling performance of commercial electrolytic manganese dioxide in Li chemistry. We leverage synchrotron X-ray analysis to discern the chemical state and local structural characteristics of Mn during cycling, as well as to quantify the Mn deposition on the counter electrode. By using an ether-based electrolyte instead of conventional carbonate electrolytes, we circumvent the formation of a surface Mn(II)-layer and Mn dissolution from LixMnO2. Consequently, we achieved an impressive similar to 100% capacity retention for MnO2 after 300 cycles at C/3. To create a lithium metal-lean full cell, we introduce hard carbon as the anode which is compatible with ether-based electrolytes. Commercial hard carbon delivers a specific capacity of similar to 230 mAh g-1 at 0.1 A g-1 without plateau, indicating a surface-adsorption mechanism. The resulting manganese dioxide
Viscosity of Mono- and Polydisperse Mixtures of Photopolymer and Rigid Spheres for Manufacturing of Engineered Composite Materials Using Vat Photopolymerization
Reynolds, John; Unterhalter, John; Francoeur, Mathieu; Bortner, Michael; Raeymaekers, Bart (Wiley-V C H Verlag, 2024-05-01)
Vat photopolymerization (VP) additive manufacturing involves selectively curing low-viscosity photopolymers via exposure to ultraviolet light in a layer-wise fashion. Dispersing filler materials in the photopolymer enables tailored end-use properties, but also increases the viscosity and the timescale associated with interparticle network structural recovery postshear. These rheological properties influence self-leveling and recoating of the liquid photopolymer mixture during VP. Herein, viscosity of photopolymer and rigid spherical glass microparticles (filler) is experimentally determined as a function of filler fraction, filler size distribution (mono- and polydisperse), shear rate, and temperature, which are important VP process parameters. Employing existing viscosity models for mono- and polydisperse polymer mixtures demonstrates that particle-particle interactions and the formation of nonspherical clusters of particles strongly affect the viscosity of both monodisperse and polydisperse mixtures with particle volume fractions > 0.05 due to agglomeration/deagglomeration of clusters at elevated shear rates. Consequently, unmodified viscosity models, which assume uniformly dispersed, rigid, spherical particles, are applicable only for mixtures with particle volume fractions < 0.05. It is shown that modifying model parameters such as the fluidity limit and intrinsic viscosity, which explicitly account for nonspherical clusters of particles, improves agreement between viscosity models and experiments, in particular when using a fractal approach.
Enhancing Electrical Conductivity of Stretchable Liquid Metal-Silver Composites through Direct Ink Writing
Zu, Wuzhou; Carranza, Hugo E.; Bartlett, Michael D. (American Chemical Society, 2024-04-30)
Structure-property-process relationships are a controlling factor in the performance of materials. This offers opportunities in emerging areas, such as stretchable conductors, to control process conditions during printing to enhance performance. Herein, by systematically tuning direct ink write (DIW) process parameters, the electrical conductivity of multiphase liquid metal (LM)-silver stretchable conductors is increased by a maximum of 400% to over 1.06 x 10(6) Sm(-1). This is achieved by modulating the DIW print velocity, which enables the in situ elongation, coalescence, and percolation of these multiphase inclusions during printing. These DIW printed filaments are conductive as fabricated and are soft (modulus as low as 1.1 MPa), stretchable (strain limit >800%), and show strain invariant conductivity up to 80% strain. These capabilities are demonstrated through a set of electromagnetic induction coils that can transfer power wirelessly through air and water, even under deformation. This work provides a methodology to program properties in stretchable conductors, where the combination of material composition and process parameters leads to greatly enhanced performance. This approach can find use in applications such as soft robots, soft electronics, and printed materials for deformable, yet highly functional devices.
Selective cross-metathesis of cellobiose derivatives with amido-functionalized olefinic structures: A model study for synthesis of cellulosic diblock copolymers
Sato, Yuuki; Sugimura, Kazuki; Edgar, Kevin J.; Kamitakahara, Hiroshi (Elsevier, 2024-09-01)
This work describes a model study for synthesis of cellulose-based block copolymers, investigating selective coupling of peracetyl beta-d-cellobiose and perethyl beta-d-cellobiose at their reducing-ends by olefin cross-metathesis (CM). Herein we explore suitable pairs of omega-alkenamides that permit selective, quantitative coupling by CM. Condensation reactions of hepta-O-acetyl-beta-d-cellobiosylamine or hepta-O-ethyl-beta-d-cellobiosylamine with acyl chlorides afforded the corresponding N-(beta-d-cellobiosyl)-omega-alkenamide derivatives with an aromatic olefin or linear olefinic structures. Among the introduced olefinic structures, CM of the undec-10-enamide (Type I olefin) and the acrylamide (Type II olefin) gave the hetero-block tetramers, N-(hepta-O-ethyl-beta-d-cellobiosyl)-N '-(hepta-O-acetyl-beta-d-cellobiosyl)-alkene-alpha,omega-diamides, with >98 % selectivity. Moreover, selectivity was not influenced by the cellobiose substituents when a Type I olefin with a long alkyl tether was used. Although the amide carbonyl group could chelate the ruthenium atom and reduce CM selectivity, the results indicated that such chelation is suppressed by sterically hindered pyranose rings or the long alkyl chain between the amido group and the double bond. Based on this model study, selective end-to-end coupling of tri-O-ethyl cellulose and acetylated cellobiose was accomplished, proving the concept that this model study with cellobiose derivatives is a useful signpost for selective synthesis of polysaccharide-based block copolymers.
Polysaccharide-based H₂S donors: Thiol-ene functionalization of amylopectin with H₂S-releasing N-thiocarboxyanhydrides
Chinn, Abigail F.; Williams, Noah R.; Miller, Kevin M.; Matson, John B. (Wiley, 2024-09-15)
Polymeric donors of gasotransmitters, gaseous signaling molecules such as hydrogen sulfide, nitric oxide, and carbon monoxide, hold potential for localized and extended delivery of these reactive gases. Examples of gasotransmitter donors based on polysaccharides are limited despite the availability and generally low toxicity of this broad class of polymers. In this work, we sought to create a polysaccharide H2S donor by covalently attaching N-thiocarboxyanhydrides (NTAs) to amylopectin, the major component of starch. To accomplish this, we added an allyl group to an NTA, which can spontaneously hydrolyze to release carbonyl sulfide and ultimately H2S via the ubiquitous enzyme carbonic anhydrase, and then coupled it to thiol-functionalized amylopectin of three different molecular weights (MWs) through thiol-ene "click" photochemistry. We also varied the degree of substitution (DS) of the NTA along the amylopectin backbone. H2S release studies on the six samples, termed amyl-NTAs, with variable MWs (three) and DS values (two), revealed that lower MW and higher DS led to faster release. Finally, dynamic light scattering experiments suggested that aggregation increased with MW, which may also have affected H2S release rates. Collectively, these studies present a new synthetic method to produce polysaccharide H2S donors for applications in the biomedical field.
A Green, Fire-Retarding Ether Solvent for Sustainable High-Voltage Li-Ion Batteries at Standard Salt Concentration
Xia, Dawei; Tao, Lei; Hou, Dong; Hu, Anyang; Sainio, Sami; Nordlund, Dennis; Sun, Chengjun; Xiao, Xianghui; Li, Luxi; Huang, Haibo; Lin, Feng (Wiley-V C H Verlag, 2024-10-01)
Lithium-ion batteries (LIBs) are increasingly encouraged to enhance their environmental friendliness and safety while maintaining optimal energy density and cost-effectiveness. Although various electrolytes using greener and safer glyme solvents have been reported, the low charge voltage (usually lower than 4.0 V vs Li/Li+) restricts the energy density of LIBs. Herein, tetraglyme, a lesstoxic, non-volatile, and non-flammable ether solvent, is exploited to build safer and greener LIBs. It is demonstrated that ether electrolytes, at a standard salt concentration (1 m), can be reversibly cycled to 4.5 V vs Li/Li+. Anchored with Boron-rich cathode-electrolyte interphase (CEI) and mitigated current collector corrosion, the LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode delivers competitive cyclability versus commercial carbonate electrolytes when charged to 4.5 V. Synchrotron spectroscopic and imaging analyses show that the tetraglyme electrolyte can sufficiently suppress the overcharge behavior associated with the high-voltage electrolyte decomposition, which is advantageous over previously reported glyme electrolytes. The new electrolyte also enables minimal transition metal dissolution and deposition. NMC811||hard carbon full cell delivers excellent cycling stability at C/3 with a high average Coulombic efficiency of 99.77%. This work reports an oxidation-resilient tetraglyme electrolyte with record-high 4.5 V stability and enlightens further applications of glyme solvents for sustainable LIBs by designing Boron-rich interphases.
Kinetics of Calcite Nucleation onto Sulfated Chitosan Derivatives and Implications for Water-Polysaccharide Interactions during Crystallization of Sparingly Soluble Salts
Knight, Brenna M.; Mondal, Ronnie; Han, Nizhou; Pietra, Nicholas F.; Hall, Brady A.; Edgar, Kevin J.; Welborn, Valerie Vaissier; Madsen, Louis A.; De Yoreo, James J.; Dove, Patricia M. (American Chemical Society, 2024-07-11)
Anionic macromolecules are found at sites of CaCO3 biomineralization in diverse organisms, but their roles in crystallization are not well-understood. We prepared a series of sulfated chitosan derivatives with varied positions and degrees of sulfation, DS(SO3-), and measured calcite nucleation rate onto these materials. Fitting the classical nucleation theory model to the kinetic data reveals the interfacial free energy of the calcite-polysaccharide-solution system, gamma(net), is lowest for nonsulfated controls and increases with DS(SO3-). The kinetic prefactor also increases with DS(SO3-). Simulations of Ca2+-H2O-chitosan systems show greater water structuring around sulfate groups compared to uncharged substituents, independent of sulfate location. Ca2+-SO3- interactions are solvent-separated by distances that are inversely correlated with DS(SO3-) of the polysaccharide. The simulations also predict SO3- and NH3+ groups affect the solvation waters and HCO3- ions associated with Ca2+. Integrating the experimental and computational evidence suggests sulfate groups influence nucleation by increasing the difficulty of displacing near-surface water, thereby increasing gamma(net). By correlating gamma(net) and net charge per monosaccharide for diverse polysaccharides, we suggest the solvent-separated interactions of functional groups with Ca2+ influence thermodynamic and kinetic components to crystallization by similar solvent-dominated processes. The findings reiterate the importance of establishing water structure and properties at macromolecule-solution interfaces.
Ethyl cellulose-block-poly(benzyl glutamate) block copolymer compatibilizers for ethyl cellulose/poly(ethylene terephthalate) blends
Chinn, Abigail F.; Trindade Coutinho, Isabela; Kethireddy, Saipranavi Reddy; Williams, Noah R.; Knott, Kenneth M.; Moore, Robert B.; Matson, John B. (Royal Society Chemistry, 2024-08-27)
Blends of petroleum-based polymers with bio-sourced polymers are an alternative to polymers derived from non-renewable resources. However, polymer blends are usually immiscible, and a compatibilizer, often a block copolymer, is required to improve mixing. In this work, we synthesized a block copolymer of ethyl cellulose (ECel) and poly(benzyl glutamate), termed ECel-block-poly(BG), and we applied it as a compatibilizer for ECel/poly(ethylene terephthalate) (ECel/PET) blends. To synthesize this block copolymer, two ECel-NH2 macroinitiators were evaluated for ring-opening polymerization of benzyl glutamate-N-thiocarboxyanhydride (BG-NTA), one with the amine directly attached to the ECel reducing chain end, and the other with a short PEG linker between ECel and the amine initiator. The PEG-containing macroinitiator led to the synthesis of a block copolymer that was unimodal by size-exclusion chromatography (SEC) while the other initiator led to uncontrolled homopolymerization of BG-NTA, presumably due to steric hindrance near the primary amine. A series of solvent studies revealed that polymerization of BG-NTA in CH2Cl2 was the best system for obtaining the ECel-block-poly(BG) block copolymer, achieving 95% conversion based on H-1 NMR spectroscopy. The success of chain extension and molecular weight analysis were evaluated using SEC with multi-angle light scattering (SEC-MALS). Blends composed of 70% ECel and 30% PET with different weight percentages (wt%) of block copolymer compatibilizer were made via solvent casting from hexafluoroisopropanol. Phase contrast optical microscopy and small-angle laser light scattering were used to probe the effectiveness of the ECel-block-poly(BG) block copolymer as a compatibilizer (5-30 wt%) for the 70/30 ECel/PET blends. A decrease in average domain size from 15 +/- 4 mu m in the base blend (without compatibilizer) to 2 +/- 1 mu m in the blend containing 30 wt% ECel-block-poly(BG) indicated successful compatibilization of the blend.
Customizing STEM organogels using PET-RAFT polymerization
Bowman, Zaya; Baker, Jared G.; Hughes, Madeleine J.; Nguyen, Jessica D.; Garcia, Mathew; Tamrat, Nahome; Worch, Joshua C.; Figg, C. Adrian (Royal Society Chemistry, 2024-10-01)
Photoinduced electron/energy transfer (PET) reversible addition-fragmentation chain transfer (RAFT) polymerization results in more uniform polymer networks compared to networks synthesized by thermally initiated RAFT polymerizations. However, how PET-RAFT polymerizations affect molecular weight control and physical properties during parent-to-daughter block copolymer network synthesis is unclear. Herein, we synthesized a structurally tailored and engineered macromolecular (STEM) organogel composed of poly(methyl acrylate) and a degradable crosslinker. Chain extensions on the STEM organogel were performed using PET-RAFT polymerization of either methyl acrylate (MA) or N,N-dimethylacrylamide (DMA) with or without additional crosslinker. We found that physical properties were dependent on monomer composition and crosslinking. The swelling ratios of the diblock networks were similar in DMAc. Conversely, swelling ratios in water increased by 430% for networks extended with MA and 5200% for networks extended with DMA compared to the parent organogels. Rheological analysis showed a tunable modulus from 1000-4000 Pa. However, size exclusion chromatography analysis of the degraded gels revealed that the PET-RAFT polymerization chain extension yielded disperse block copolymers with poor control over the molecular weight. These results indicate that PET-RAFT polymerizations can be used to expand organogel networks to block copolymer networks to modulate physical properties, but control over the chain extension polymerization is lost. Looking forward, this report points to opportunities to gain control over PET-RAFT block copolymer network synthesis via secondary reversible deactivation pathways. PET-RAFT polymerization was used to modify STEM organogels, while degradable linkers enabled the characterization of the resulting block copolymers.

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