Polyelectrolyte Research Articles

A Multiphysics Model Simulating the Electrochemical, Thermal, and Thermal Runaway Behaviors of Lithium Polymer Battery

Lithium-ion batteries (LIBs) have circumvented the energy storage landscape for decades. However, safety concerns about liquid–electrolyte-based LIBs have challenged their mobilization. Lithium polymer (LiPo) batteries have gained rising interest due to their high thermal stability. Despite an array of commercially available LiPo batteries, limited studies have ventured into modeling. Numerical simulations allow low-cost optimization of existing battery designs through parameter analysis and material configuration, leading to safer and more energy-efficient batteries. This work examined the electrochemical, thermal, and thermal runaway behavior of a lithium cobalt oxide cathode, graphite anode, and poly(vinylidene fluoride-hexafluoropropylene) electrolyte pouch-type LiPo battery using COMSOL Multiphysics®, and validated results with experimental data. The simulated potential curve exhibited strong agreement with experiment data, while the temperature profile during discharge displayed qualitative discrepancies rationalized by the reversible heat generation. Thermal runaway simulations via oven tests revealed that the highest heat generation is from the cathode–electrolyte reaction, while the solid electrolyte interface decomposition initiates the heat generation process. These results suggest a thorough selection of cathode and electrolyte material to heighten battery safety. Overall, the developed models can be utilized as design tools to investigate various chemistries and designs to estimate the behavior and performance of batteries.

Photosensitive Spherical Polymer Brushes: Light-Triggered Process of Particle Repulsion

We report on a light-triggered process at which repulsive interactions between microparticles with a polyelectrolyte (PE) brush coating can be remotely controlled. The spherical polyelectrolyte brushes are loaded with photosensitive azobenzene containing surfactant which can undergo reversible photo-isomerization from trans to cis state. The surfactant hydrophilicity is altered by illumination with light of an appropriate wavelength, at which a dynamic exchange of the more surface-active trans isomer in comparison to the more water soluble cis isomer with the PE brush generates a concentration gradient of the cis isomers near a solid surface where the particle is sedimented. In this way, each spherical brush produces its local lateral diffusioosmotic flow pointing outside in a radial direction resulting in mutual long-range repulsive interactions. We demonstrate that a PE layer has a higher tendency to absorb surfactant in comparison to plain silica particles, yielding a larger flow strength. This correlation holds true up to a critical intensity, where the dynamic exchange is adsorption limited with respect to trans isomers and especially pronounced for the PE-coated particles.

Stability of layer-by-layer nanofiltration membranes in highly saline streams

Layer-by-layer (LBL) assembly is an essential method for the preparation of nanofiltration (NF) membranes, offering tunable charge and pore size, high water permeability, and good anti-fouling properties, making them highly suitable for resource recovery, seawater desalination, and other fields. Despite their advantages, LBL NF membranes suffer from salinity instability, limiting their use in highly saline streams. This perspective review provides a summary of the fundamental physical and chemical principles of LBL assembly related to the salinity stability of LBL NF membranes. We critically analyze the driving force of LBL assembly, the binding strength of polyelectrolyte (PE) pairs, and the overcompensation of LBL membranes. We also discuss the factors affecting overcompensation level with respect to two different time scales. Furthermore, we examine the relationship between overcompensation level and salinity stability of LBL membranes, considering physical (osmotic pressure) and chemical (Le Chatelier's principle) aspects. Our analysis demonstrates that the salinity stability of LBL NF membranes in highly saline solutions can be improved by selecting PEs with stronger binding strength, increasing the overcompensation level, and chemical crosslinking. These methods not only enhance the salinity stability of LBL NF membranes but also offer greater potential for their future application in highly saline streams.

Chitosan-Bead-Encapsulated Polystyrene Sulfonate for Adsorption of Methylene Blue and Regeneration Studies: Batch and Continuous Approaches.

Textile industrialization causes water pollution due to the discharge of industrial effluents into the environment. To reduce the impact of industrial effluent, it must be treated in wastewater treatment plants before discharge into rivers. Among all wastewater treatment approaches, the adsorption process is one method to remove pollutants from wastewater, but it has some limitations in term of reusability and ionic selective adsorption properties. In this study, we prepared cationic poly (styrene sulfonate) (PSS)-incorporated anionic chitosan beads synthesized using the oil-water emulsion coagulation method. The produced beads were characterized using FESEM and FTIR analysis. In batch adsorption studies, the PSS-incorporated chitosan beads exhibited monolayer adsorption processes, that is, exothermic processes that occur spontaneously at low temperatures, which were analyzed based on the adsorption isotherms, adsorption kinetics, and thermodynamics model fittings. The presence of PSS enables cationic methylene blue dye to adsorb to the anionic chitosan structure via electrostatic interaction between the sulfonic group and the dye molecule. The maximum adsorption capacity of PSS-incorporated chitosan beads achieved 42.21 mg/g, as calculated from the Langmuir adsorption isotherm. Finally, the PSS-incorporated chitosan beads demonstrated good regeneration with different types of reagents, especially using sodium hydroxide as a regeneration reagent. With the use of sodium hydroxide regeneration of this adsorbent material, a continuous adsorption setup also demonstrated that PSS-incorporated chitosan beads can be reused for methylene blue adsorption for up to three cycle processes.

Two dimensional MoS2 finding its way towards constructing high-performance alkaline recovery membranes

The available alkaline recovery membranes are currently dominated by polymeric materials, but they suffer from a permeation-selectivity trade-off and inferior chemical resistance. Robust two dimensional (2D) lamellar membranes with sub-nanometer wide channels are promising candidates for discerning OH− and other anions. Here, we report the development of alkaline recycling membranes through stacking MoS2 nanosheets. Benefiting from the ordered and narrow 2D channels, MoS2 membranes show excellent alkaline recovery performances. The OH− dialysis coefficient (UOH-) and separation factor (S) towards simulated OH− and WO42- across the 500 nm thick MoS2 laminates reach 6.9 × 10−3 m·h−1 and 34.3 respectively. Furthermore, the chemical environments of MoS2 laminates were modulated by intercalating ionic poly(sodium 4-styrene sulfonate) (PSS@MoS2). The UOH- and S values of PSS@MoS2 membrane further improve to 11.7 × 10−3 m·h−1 and 49.8 respectively. Besides, both MoS2 and PSS@MoS2 membranes exhibit promising stability.

Light excitation of gold Nanorod-Based hybrid nanoplatforms for simultaneous bimodal phototherapy

In this work, we developed a hybrid nanosystem able to simultaneously combine its potential as a photodynamic (PDT) and plasmonic photothermal (PPTT) therapeutic agent to kill malignant cells. To do that, AuNRs were functionalized by means of the layer-by-layer (LbL) assembly technique using alternating layers of anionic poly(styrene sulfonate) (PSS) and cationic poly-L-lysine (PLL) as polyelectrolytes (PEs), and an outer final layer of hyaluronic acid (HA) to provide the hybrid particles with both sufficient colloidal stability and targeting ability to tumoral cells overexpressing CD44 receptors. To provide the nanoplatform with PDT capabilities, the near-infrared (NIR) sensitive photosensitizer (PS) indocyanine green (ICG) was previously grafted to the PLL PE and assembled on the particle surface coating; in this manner, PSS/PLL-ICG/HA-coated AuNRs hybrid particles were obtained. Then, the conditions for optimized reactive oxygen species (ROS) production under NIR light excitation were elucidated, reaching ca. 80% after 5 min irradiation at 2.0 W/cm2 compared to positive control (H2O2). Since ICG can also absorb near infrared (NIR) light and transforms it by internal conversion into heat under suitable irradiation conditions, which adds to the photothermal plasmonic effect provided by the metallic NP, the heating profiles provided by the present hybrid nanoparticles (NPs) were measured, being observed temperature increments ranging from 9 to 22 °C. The potential contribution of its different components to both PDT and PPTT were deeply analyzed in vitro for intended cancer therapeutics at several power intensities but also at different temperatures with the aim of elucidating the role played by both phototherapies on cell cytotoxicity, the optimal illumination conditions for effective bimodal phototherapy as well as the elucidation of the main cell death mechanism involved. Under optimized conditions and after the administration of 2.5 ·1010 NPs/mL, cell cytotoxicites of up to ca. 70% were determined by combination of PDT + PPTT therapeutic effect.

Gold Nanoparticle–Polyelectrolyte Complexes with Tunable Structure Probed by Synchrotron Small-Angle X-ray Scattering: Implications for the Production of Colloidal Crystals-Based Nanophotonic Materials

Close-packed colloidal crystals of gold nanoparticles (AuNPs) are of great interest in the field of nanophotonics due to their lattice-pattern-dependent optical properties. One challenge resides in producing such crystalline assemblies by a scalable approach involving polydisperse AuNPs obtained by standard synthesis routes and structuring natural molecules in water at room temperature. Electrostatic complexation between functionalized AuNPs and oppositely charged polyelectrolytes (PELs) is a very simple way to create AuNP self-assemblies of different morphologies and compactness. Our work investigates, using synchrotron small-angle X-ray scattering, their structure as a function of concentration, PEL persistence length and ionic strength. By decreasing the radius, R, of the positively charged gold nanoparticles to a few nm (R ≤ 3 nm) and increasing the polyelectrolyte persistence length, LT, substituting flexible sodium polystyrenesulfonate for natural semiflexible hyaluronan, we tuned the characteristic ratio LT/R up to values of ≥1.85. Such ratios allow the successful formation of a new AuNPs arrangement with a high degree of short-range order at low ionic strength and of crystalline order when interactions are screened by addition of salt. This approach involving commercially available natural water-soluble semiflexible PELs, opens a low-cost and promising way for the one-step production of gold colloidal crystals, which can be of ubiquitous utility in nanophotonics.

Facile and binder-free fabrication of deep colors on cotton fabrics with hand-feel enhancement via screen printing

Screen printing with pigments features its superiority and versatility and has shown promising applications in color-related fields, whereas pigments have clear advantages among colorants owing to their wide color-range, extensive applicability, and green characteristics such as water and energy saving. However, it requires massive, inevitable addition of binders to improve the affinity and dispersity of pigments during printing, which results in undesired rigidity of printed fabrics. Here, we synthesized an anionic poly (styrene-methyl methacrylate-acrylic acid) absorbed Rhodamine B (RB@PSMA) nanosphere via soap-free emulsion polymerization for printing the cotton fabrics without binders. The prepared color nanospheres RB@PSMA show the good size stability (PDI=0.018) and dispersity (< 299.4 nm). Notably, the strong electrostatic attraction from PSMA nanosphere enables the saturated adsorption of Rhodamine B dyes with ionic bonding. The printed fabrics with RB@PSMA were thus endowed with enhanced color performance (X 2.3 in K/S value) and soft hand feel without binders, differing from original RB printed ones that are usually stiff due to the crosslinking-induced rigidity. This approach may carve a practical avenue in binder-free pigment coloring and provide new prospects for the facile and versatile design of other printing and dyeing technology.

Structure and Dynamics of Hybrid Colloid-Polyelectrolyte Coacervates.

We develop a scaling theory for the structure and dynamics of "hybrid" complex coacervates formed from linear polyelectrolytes (PEs) and oppositely charged spherical colloids, such as globular proteins, solid nanoparticles, or spherical micelles of ionic surfactants. At low concentrations, in stoichiometric solutions, PEs adsorb at the colloids to form electrically neutral finite-size complexes. These clusters attract each other through bridging between the adsorbed PE layers. Above a threshold concentration, macroscopic phase separation sets in. The coacervate internal structure is defined by (i) the adsorption strength and (ii) the ratio of the resulting shell thickness to the colloid radius, H/R. A scaling diagram of different coacervate regimes is constructed in terms of the colloid charge and its radius for Θ and athermal solvents. For high charges of the colloids, the shell is thick, H ≫ R, and most of the volume of the coacervate is occupied by PEs, which determine its osmotic and rheological properties. The average density of hybrid coacervates exceeds that of their PE-PE counterparts and increases with nanoparticle charge, Q. At the same time, their osmotic moduli remain equal, and the surface tension of hybrid coacervates is lower, which is a consequence of the shell's inhomogeneous density decreasing with the distance from the colloid surface. When charge correlations are weak, hybrid coacervates remain liquid and follow Rouse/reptation dynamics with a Q-dependent viscosity, η Rouse ∼ Q 4/5 and η rep ∼ Q 28/15 for a Θ solvent. For an athermal solvent, these exponents are equal to 0.89 and 2.68, respectively. The diffusion coefficients of colloids are predicted to be strongly decreasing functions of their radius and charge. Our results on how Q affects the threshold coacervation concentration and colloidal dynamics in condensed phases are consistent with experimental observations for in vitro and in vivo studies of coacervation between supercationic green fluorescent proteins (GFPs) and RNA.

Synthesis of AgNPs and ZnONPs using tea leaves extract and their utilization to improve dyeability, printability and functionality of cotton and wool fabrics

Finishing is to make textiles more appealing to consumers by attaining a number of objectives like as functionalization, increased quality, and improved performance. Polymers are increasingly being used instead of simple chemicals to improve multiple useful features in most natural and synthetic fibres, such as absorbency, antibacterial protection, and ultraviolet protection. The use of nanotechnology in textile finishing has helped to improve the quality and performance of textile materials by giving new and more sophisticated capabilities to textile substrates as well as boosting current functionality such as durability, antibacterial, and UV protection (UPF). The proclivity of metal nanoparticles, such as AgNPs and ZnONPs, to interact with microbes has affected desired results in textile materials. Tea leaf extract was used to create AgNPs. ZnONPs were calcined from the powder produced by reacting zinc acetate with tea leaf extract. The fabric is coated with polycation (PC) and metal nanoparticles that have been produced.

Swelling and shrinking of two opposing polyelectrolyte brushes.

Salt concentration and confinement effects affect the configuration of polyelectrolyte (PE) brushes due to electrostatic interactions. In this work, we develop a new theoretical model to analyze the electrostatics and swelling-shrinking behavior of two opposing PE brushes. By comparing three length scales, i.e., equilibrium brush height, separation distance, and Debye length, we obtain distinct scaling laws for brush height in different regimes. We provide explanations for the anomalous shrinkage of the PE brush with added salt reported in experiments and simulations, the applicability of the homogeneous brush assumption, and the confinement effect on the brush height. Our model can be used to shed light on the configuration and functionalities of PE-grafted interfaces, which play important roles in ion selective membranes and organism lubrication. We also anticipate that our method will be useful to understand the functionalities of other charged soft matter systems, such as hydrogel swelling and colloidal stability.

Carboxylated Cellulose Nanocrystals Decorated with Varying Molecular Weights of Poly(diallyldimethylammonium chloride) as Sustainable Antibacterial Agents

Cationic nanomaterials are promising candidates for the development of effective antibacterial agents by taking advantage of the nanoscale effects as well as other exceptional physicochemical properties of nanomaterials. In this study, carboxylated cellulose nanocrystals (cCNCs) derived from softwood pulp were coated with cationic poly(diallyldimethylammonium chloride) of varying molecular weights. The resulting cationic carboxylated cellulose nanocrystals coated with poly(diallyldimethylammonium chloride) (cCNCs-PDDA) nanomaterials were characterized for their structural and morphological properties using Fourier transform infrared spectroscopy, dynamic light scattering, zeta potential, elemental analysis, transmission electron microscopy, and thermogravimetric analysis. Cationic cCNCs-PDDA were investigated for their antibacterial properties against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli 23934 and Pseudomonas aeruginosa using a bacterial lawn growth inhibition assay. cCNC-PDDA materials displayed marked antibacterial activity, particularly against Gram-positive Staphylococcus aureus. Overall, our results indicated that cCNCs-PDDA could be a potential candidate for antibacterial applications such as antibacterial surfaces or coatings.

Engineering polyelectrolyte multilayer coatings as a strategy to optimize enzyme immobilization on a membrane support

This study presents a systematic design of a biocatalytic membrane reactor, where we combined physical adsorption and chemical conjugation of Alcohol Dehydrogenase (ADH) in a novel type of polyelectrolyte (PE) layer-by-layer (LbL) assembly system. The hybrid LbL structure is proposed as a strategy to simultaneously advance activity and operational stability of enzymes immobilized on a membrane surface. Using poly(allylamine hydrochloride) (PAH) and poly(methacrylic acid) sodium salt (PMAA) allowed functionalization of polysulfone (Psf) membrane for subsequent ADH immobilization with no resistance to substrate mass transfer and no decrease in water permeability (WP) (56.5 ± 8.8 Lm−2h −1bar−1) compared to the pristine membrane (50.8 ± 1.7 Lm−2h−1bar−1). Tailoring membrane surface chemistry, enzyme concentration, time, and pH during the adsorption step allowed to increase specific activity of the biocatalytic membrane from 1.13 ± 0.18 mU/cm2 for immobilization on the pristine membrane to 4.09 ± 0.53 mU/cm2 for immobilization on a PAH-modified coating. Conjugation of adsorbed ADH with PMAA layer improved reusability compared to the non-conjugated membrane (by retaining 73.4 ± 3.2% of the starting activity on the third conversion run against 58.7 ± 2.4%) and shifted pH optimum by 1 unit compared to the free ADH. The presented approach of LbL assembly synthesis provides a potential foundation for engineering of biocatalytic nanoscale reactors.

Topical Administration of Verapamil in Poly(ethylene glycol)-Modified Liposomes for Enhanced Sinonasal Tissue Residence in Chronic Rhinosinusitis: Ex Vivo and In Vivo Evaluations.

Verapamil is a calcium channel blocker that holds promise for the therapy of chronic rhinosinusitis (CRS) with and without nasal polyps. The verapamil-induced side effects limit its tolerated dose via the oral route, underscoring the usefulness of localized intranasal administration. However, the challenge to intranasal administration is mucociliary clearance, which diminishes localized dose availability. To overcome this challenge, verapamil was loaded into a mucoadhesive cationic poly(ethylene glycol)-modified (PEGylated) liposomal carrier. Organotypic nasal explants were exposed to verapamil liposomes under flow conditions to mimic mucociliary clearance. The liposomes resulted in significantly higher tissue residence compared with the free verapamil control. These findings were further confirmed in vivo in C57BL/6 mice following intranasal administration. Liposomes significantly increased the accumulation of verapamil in nasal tissues compared with the control group. The developed tissue-retentive verapamil liposomal formulation is considered a promising intranasal delivery system for CRS therapy.

Nonreciprocal oscillations of polyelectrolyte gel filaments subject to a steady and uniform electric field

Soft actuators typically require time-varying or spatially modulated control to be operationally effective. The scope of the present paper is to show, theoretically and experimentally, that a natural way to overcome this limitation is to exploit mechanical instabilities. We report experiments on active filaments of polyelectrolyte (PE) gels subject to a steady and uniform electric field. A large enough intensity of the field initiates the motion of the active filaments, leading to periodic oscillations. We develop a mathematical model based on morphoelasticity theory for PE gel filaments beating in a viscous fluid, and carry out the stability analysis of the governing equations to show the emergence of flutter and divergence instabilities for suitable values of the system’s parameters. We confirm the results of the stability analysis with numerical simulations for the nonlinear equations of motion to show that such instabilities may lead to periodic self-sustained oscillations, in agreement with experiments. The key mechanism that underlies such behaviour is the capability of the filament to undergo active shape changes depending on its local orientation relative to the external electric field, in striking similarity with gravitropism, the mechanism that drives shape changes in plants via differential growth induced by gravity. Interestingly, the resulting oscillations are nonreciprocal in nature, and hence able to generate thrust and directed flow at low Reynolds number. The exploitation of mechanical instabilities in soft actuators represents a new avenue for the advancement in engineering design in fields such as micro-robotics and micro-fluidics.

Synthesis of pH-responsive polyzwitterions for activated cellular uptake and tumor accumulation of gold nanoparticles at tumorous acidity

The response sensitivity of surface material plays an important role in adjustable nano-bio interaction in vivo. In this present, a zwitterionic polymer (polyzwitterion) containing quaternary ammonium cation and sulfonamide anion poly(4-((4-(3-(methacryloyloxy)propoxy)phenyl) sulfonamido)-N, N, N-trimethyl-4-oxobutan-1-aminium chloride) (PMPTSA) was synthesized by Reversible Addition-Fragmentation Chain Transfer Polymerization (RAFT) polymerization to explore the pH responsive behavior in tumors. The PMPTSA-coated gold nanoparticles (PMPTSA-@-Au NPs) showed zwitterionic nature such as antifouling ability, low cellular uptake and prolonged circulation time similar with common hydrophilic polymers, including polyethylene glycol (PEG), poly(carboxybetaine methacrylate) and poly(sulfobetaine methacrylate) functional gold nanoparticles in physiological environment (pH 7.4). A high sensitivity and reversible positive charge conversion of P(MPTSA)-@-Au NPs at tumor slight acidic microenvironment (∼pH 6.8) leaded to an enhanced cellular internalization than that at pH 7.4 and increased tumor accumulation compared with PEG, polycarboxybetaines and polymer sulphobetaine (PSB) functional gold nanoparticles. The highly pH responsive PMPTSA will provide the promising application in cancer nanomedicine.

Fabrication of Polystyrene Sulfonate-Chitosan (PSS-Chitosan) Membrane as Dodecyl Benzene Sulfonate (DBS) Adsorbent in Laundry Wastewater

The combination of polystyrene and chitosan can form polyelectrolyte (PE) membranes. Polystyrene sulfonate-chitosan (PSS-chitosan) adsorbent membrane can adsorb dodecyl benzene sulfonate (DBS) in laundry wastewater. This study aimed to synthesize, identify characteristics, and formulate adsorption effectiveness by PSS-chitosan membranes. The research methods included converting polystyrene into PSS, isolating chitosan, optimizing geometry, making PSS-chitosan membranes, studying adsorption, and applying membranes to laundry wastewater. The resulting membrane was characterized using FTIR and SEM. The results of the infrared spectra showed vibrations of –OH and –NH2 groups at 3418 cm–1, while the SEM image showed a homogeneous membrane surface. The quality of chitosan isolation from shrimp shells was indicated by the degree of deacetylation of 61.3%. The results of the geometry optimization showed the change in the structure’s total energy after adsorption. The PSS-chitosan membrane is resistant to acids but decomposes under alkaline conditions. Optimum adsorption of PSS-chitosan membrane on DBS occurred at pH 8 for 100 minutes. The adsorption kinetics of the PSS-chitosan membrane follows the first pseudo-order equation. PSS-chitosan membrane adsorption isotherm follows the Langmuir isotherm model with an adsorption capacity and efficiency of 3.97 mg.g–1 and 76.6%, respectively, at 0.6 ppm. At the application stage, the PSS-chitosan membrane could adsorb DBS in laundry wastewater by (62.4 ± 7.2) %.

Surface‐Attached Polymer Networks Made from Cationic Poly(diitaconates): Synthesis, Surface Characterization, and Bioactivity

AbstractFacially amphiphilic polymers carrying cationic and hydrophobic groups on the same repeat unit have shown promising antimicrobial activity and biocompatibility, yet they are prone to suffer from protein adhesion which may induce biofilm formation. To overcome this problem, poly(diitaconate)‐based copolymers with cationic/hydrophobic and protein‐repellent/charge‐neutral repeat units are synthesized. The bioactivity profile of surface‐attached polymer networks made from these copolymers depends on the ratio of the cationic and charge‐neutral repeat units. In all cases, the protein adhesion is substantially reduced compared to purely cationic polymers. At a 50:50 ratio, the polymer coatings are partially protein‐repellent and antimicrobial, yet slightly cell toxic. At an intermediate composition of 30:70, they are still antimicrobial and the cell compatibility is substantially improved. The long‐term stability of these materials still has to be determined to judge their suitability for medical applications.

Charge-Selective Aggregation Behavior of Thermoresponsive Polyelectrolytes Having Low Charge Density in Aqueous Solutions of Organic Counterions

The aggregation behavior of thermoresponsive polyelectrolytes with low charge density in aqueous solutions of organic counterions was investigated. We synthesized two thermoresponsive polyelectrolytes: anionic poly(N-isopropylacrylamide-co-(3-sulfopropyl)acrylamide potassium) (P-NIP-SPAK) and cationic poly(N-isopropylacrylamide-co-(3-acrylamidepropyl)trimethylammonium chloride) (P-NIP-AAPTAC). The polyelectrolytes remained soluble in their aqueous solutions even above the lower critical soluble temperature of P-NIP owing to the strong hydration property of the ionic groups. The aggregation occurred when organic counterions were added to the solution. In these solution systems, the concentration of counterions exceeds those of ionic groups introduced into the polyelectrolytes. The aggregation behavior is attributed to the salting-out effect of counterions accommodated near the polyelectrolyte surface by electrostatic interaction. This aggregation behavior was utilized for the charge-selective recognition of amino acids. P-NIP-SPAK aggregated only when basic amino acids were added under acidic conditions, whereas P-NIP-AAPTAC aggregated only when acidic amino acids were added under basic conditions. The results herein demonstrate that P-NIP-SPAK and P-NIP-AAPTAC have the potential to be used as charge-selective polymer sensors for amino acids without having to strictly control the experimental conditions.

Chemistry-Informed Machine Learning for Polymer Electrolyte Discovery.

Solid polymer electrolytes (SPEs) have the potential to improve lithium-ion batteries by enhancing safety and enabling higher energy densities. However, SPEs suffer from significantly lower ionic conductivity than liquid and solid ceramic electrolytes, limiting their adoption in functional batteries. To facilitate more rapid discovery of high ionic conductivity SPEs, we developed a chemistry-informed machine learning model that accurately predicts ionic conductivity of SPEs. The model was trained on SPE ionic conductivity data from hundreds of experimental publications. Our chemistry-informed model encodes the Arrhenius equation, which describes temperature activated processes, into the readout layer of a state-of-the-art message passing neural network and has significantly improved accuracy over models that do not encode temperature dependence. Chemically informed readout layers are compatible with deep learning for other property prediction tasks and are especially useful where limited training data are available. Using the trained model, ionic conductivity values were predicted for several thousand candidate SPE formulations, allowing us to identify promising candidate SPEs. We also generated predictions for several different anions in poly(ethylene oxide) and poly(trimethylene carbonate), demonstrating the utility of our model in identifying descriptors for SPE ionic conductivity.