Abstract Poly(ethylene glycol) (PEG) is an industrial polymer, employed widely in biomedical, pharmaceutical, and materials applications due to its biocompatibility, water solubility, and stability. However, its end group and architectural diversity and susceptibility to oxidative and environmental degradation complicate precise molecular characterization. This study employed a multidimensional mass spectrometric approach, combining matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) with high-resolution mass spectrometry (MS), trapped ion mobility (IM) separation, and tandem mass spectrometry (MS/MS) fragmentation for the comprehensive compositional, structural, and architectural analysis of a degraded sample of methoxy poly(ethylene glycol) methacrylate (mPEG-methacrylate), a hydrophilic polymer used for the preparation of hydrogels and antifouling surfaces. MALDI-MS provided molecular-level resolution of the major degradation products, which included a small amount of surviving mPEG-methacrylate and significant quantities of new products, generated by modification or oligomerization of the methacrylate functionality. Comb-shaped copolymers with double bond and/or oxidized polymethacrylate chain ends were the predominant degradants. ESI-IM-MS added a rapid gas-phase separation dimension, resolving PEG chains according to both charge state and molecular shape and rendering ion mobilities (collision cross-sections) indicative of the architectural diversity produced during degradation. Products invisible by MALDI-MS could be identified, inter alia, as mPEG from ester hydrolysis and poly(mPEG-methacrylate)s with high degrees of polymerization. Charge-dependent mobility trends confirmed variations in polymer compactness depending on the number of PEG side chains, while MS/MS analysis validated the formation of comb architectures and revealed remarkable robustness for methoxy-capped polyether chains. This multidimensional MS strategy offers an advanced framework for the detailed structural elucidation of complex materials and formulations, capturing both the intact polymeric architecture and degradation-derived chemical diversity reflecting the sample’s age and usage. The integration of MALDI-MS and ESI-IM-MS enables simultaneous analysis of molecular weight, primary structure, architecture, and functional heterogeneity, thus providing critical insights into the synthesis, stability, and reactivity of industrial polymers.
Abstract Lignosulfonates (LS) have long set the standard of dispersants for construction, agrochemical, oilfield, and animal feed industries, due to their amphiphilic structure─aromatic domains linked with sulfonated functionalities, which result in efficient and cost-effective colloidal stabilization. Nevertheless, LS production is intrinsically limited by the falloff in sulfite pulping, which is today only a minor percentage of the world’s pulp manufacturing. On the other hand, kraft lignin (KL) is produced at multimillion-tonne levels annually and is now being acknowledged as a renewable aromatic polymer of strategic importance. Recent studies indicate that fractionation and controlled functionalization of KL can produce dispersants that match or outperform LS in selected systems, providing quantitative evidence that its chemical tunability can translate into competitive dispersant performance under defined application conditions. But these benefits come with problems of heterogeneity, process complexity, scalability, and cost. This Perspective argues that, owing to its chemical tunability, industrial availability, and potential for process innovation, KL should be regarded not as a universal replacement for LS, but as a platform capable of competing in next-generation dispersant systems where tailored performance justifies additional processing. By combining chemistry, technology limitations, and economics, lignin-based materials have proven to be important enablers of circular and low-carbon industrial technologies.
Abstract Plasticizers are small molecule additives compounded with polymers to tune their physical properties and facilitate processing, but plasticizers often leach from plastics, where they potentially have negative environmental and ecological consequences. Synthetic design can obviate the need for plasticizers by identifying a polymer with the required properties for an application without the need for external additives. In particular, designing isosteric analogues to commercial polymers that preserve key functionality while expanding the range of accessible thermal and mechanical properties would provide benefits beyond conventional copolymerization or side-chain modification strategies. Here, we demonstrate that a simple and efficient postpolymerization modification procedure provides access to poly(vinyl ether-co-vinyl alcohol) copolymers which are isosteric analogues of poly(vinyl butyral) (PVB). These copolymers exhibit thermal and rheological properties that are complementary to plasticized PVB and existing PVB-like polymers. The ability to tune both density of hydroxyl groups and vinyl ether side chain provided a library of copolymers with glass transition temperatures ranging from −54 to 18 °C. Rheological characterization confirmed that these materials behaved as entangled polymer melts at room temperature, with moduli and relaxation dynamics that depended on both hydroxyl content and side chain identity. Overall, this study demonstrates the value of creating isosteric analogues to commercial polymers that diversify their properties, with the potential for reducing the use of leachable small molecule additives.
Quantitative chemical characterization of postconsumer plastics is challenging because of the large number of polymer chemistries and additives used in formulating plastic products. Plasticizers are an important family of additives used to lower the glass transition temperature and enhance flexibility in polymer formulations. However, their identification and quantification are difficult in recycling and end-of-life processes. This study critically assesses two analytical techniques for their suitability in plasticizer identification: mass spectrometry (high resolution, selectivity, and sensitivity) and time-gated Raman spectroscopy (nondestructive, quicker, and minimal sample preparation). Here, we generate searchable libraries for the identification of 91 common plasticizers using these two techniques, along with the development of reliable tools to measure their spectral similarity. We then analyze the reliability of identifications based on time-gated Raman and/or liquid chromatography-mass spectrometry with atmospheric pressure chemical ionization, explicitly highlighting the advantages and disadvantages of each technique for a given plasticizer chemical family. We have applied these tools to identify and quantify plasticizers in a NIST Standard Reference Material (SRM 2860, Phthalates in Polyvinyl Chloride).
Biobased covalent adaptable networks (CANs, vitrimers) that combine high glass transition temperatures, mechanical robustness, and reprocessability remain scarce, particularly in vinylogous urethane vitrimer chemistry. Herein, we report the synthesis of rigid vinylogous urethane CANs derived from biobased d-isosorbide bis-acetoacetate and the furfural-based diamine propane-2,2-di-(2-furylmethylamine) (PDFA). The materials were prepared by a solvent-free bulk curing strategy using mixtures of di- and trifunctional amines, enabling direct formation of cross-linked networks without additional processing solvents. The use of PDFA significantly increased the renewable carbon content while maintaining the rigidity required for glassy high-performance materials. The resulting networks exhibited tunable thermomechanical properties depending on amine structure and composition, with glass transition temperatures up to 125 °C and thermal stability up to 290 °C. Stress-relaxation experiments confirmed fast catalyst-free bond exchange in the rubbery state, with relaxation occurring on the scale of tens to hundreds of seconds and activation energies dependent on the diamine structure. Selected materials displayed efficient reprocessability by compression molding while largely preserving their thermal and tensile properties after recycling. These results demonstrate that combining d-isosorbide with a rigid furfural-derived diamine is an effective strategy toward biobased, glassy vinylogous urethane vitrimers that unite high renewable carbon content, elevated service temperature, and recyclability.
The growing demand for more sustainable polymeric materials has driven significant interest in renewable sources. In this context, nonisocyanate polyurethanes (NIPUs) represent a promising alternative to conventional polyurethanes , as they eliminate the use of toxic isocyanates. Different synthetic routes for polyurethanes without isocyanate have been developed in recent years. Among them, the polyaddition of cyclic carbonates (CCs) and diamines has attracted particular attention. The availability of various biobased feedstocks for cyclic carbonate synthesis has led to growing research in this area. Biobased feedstocks for the preparation of cyclic carbonates (CCs) can be broadly categorized into four main groups: (i) vegetable-oil-derived feedstocks (e.g., triglycerides and unsaturated fatty acids); (ii) lignocellulosic-biomass-derived phenolic compounds, including lignin derivatives (e.g., vanillin and guaiacol), tannins, and cardanol; (iii) carbohydrates and polyols, such as glucose, sucrose, starch, cellulose, glycerol, sorbitol, and mannitol; and (iv) terpene-derived compounds, such as limonene and rosin (a diterpene-based natural resin mainly composed of abietane-type resin acids). Glycerol, a renewable, abundant, and low-cost byproduct of industrial processes such as biodiesel production, is an attractive candidate for cyclic carbonate synthesis. This review provides a comprehensive overview of the conversion of glycerol into cyclic carbonate precursors, especially glycerol carbonate and diglycerol dicarbonate, and their role in NIPU synthesis. Particular emphasis is placed on the application of NIPUs derived from these cyclic carbonates in foams, adhesives, and coatings. This article highlights the advancements in the synthesis, properties, and performance of glycerol-based NIPUs over the past decade. By showing the progress and challenges of using these biobased feedstocks, this review contributes to the ongoing research toward sustainable NIPUs.
Skeletal muscle plays a crucial role in metabolic homeostasis, but severe injuries such as volumetric muscle loss (VML) compromise its regenerative capacity. Current clinical strategies have limitations, prompting the exploration of alternative therapies. Hydrogels, with their tunable properties, are promising for modulating the regenerative microenvironment and supporting muscle regeneration. While existing reviews have addressed hydrogels in muscle regeneration, this comprehensive Review offers a uniquely integrated and in-depth examination of the field. We systematically investigate design principles, advanced fabrication strategies, and critical considerations for translational application, including electroactive, immunomodulatory, and spatiotemporal delivery functionalities, alongside state-of-the-art techniques such as 3D bioprinting and electrospinning. Furthermore, this Review thoroughly assesses the multifaceted challenges in clinical translation, meticulously addressing preclinical limitations, scalability, manufacturability, regulatory pathways, and long-term safety, thereby providing a more comprehensive discourse than often encountered in existing literature. By integrating insights from muscle biology and advanced materials science, this review aims to offer a refined perspective on overcoming current barriers, informing the development of next-generation hydrogel-based therapies for severe skeletal muscle injuries.
Advances in hydrogel research have enabled the design of bulk networks with diverse functionalities; however, precise control of interfacial properties remains a key challenge to expanding their applications, particularly in biointerfaces. Here, we report a simple and versatile surface functionalization strategy based on the self-assembly of terminally modified cello-oligosaccharides. When azido-functionalized cello-oligosaccharides dissolved in 85% phosphoric acid are applied to hydrogel surfaces, mixing with the intrinsic water within the hydrogels induces rapid self-assembly, forming nanostructured granular coatings at the interface. This method is applicable to both chemically and physically cross-linked hydrogels. The resulting azido-functionalized surfaces enable postfunctionalization via click chemistry, allowing biomolecule immobilization. As a proof of concept, antigen-conjugated hydrogels were used for the detection of specific immunoglobulin G, exhibiting selective responses even in serum-containing environments due to the antibiofouling properties of the assemblies. These findings establish terminally modified cello-oligosaccharides as a new class of interfacial modifiers for hydrogels, providing a facile route to biofunctional and antifouling interfaces for sensing and diagnostic applications.
A series of 100 "shaped" ABC coil-brush triblock terpolymers were prepared by sequential living ring-opening metathesis polymerization (ROMP) of 5-norbornene-2,3-exo,exo-dicarboxylic acid dimethyl ester (M) and norbornenyl diester macromonomers P a and P b , each bearing two identical side chains that are precise oligomers of poly-(ethylene-alt-propylene) containing a,b = 1, 2, 4, or 9 repeat units. These MP a P b block terpolymers were designed such that the more polar coil M block melt microphase separates from the mutually miscible P a and P b segments (a ≠ b), which form a digitally shaped bottlebrush segment, in order to assess how bottlebrush shape affects block copolymer network phase stability. Thus, samples with total M n = 7-30 kg/mol, dispersities 1.02 ≤ Đ ≤ 1.04, and volumetric compositions 0.26 ≤ f M ≤ 0.58 were chosen to target the region where network phases such as the double gyroid (GYR) might be expected. Small-angle X-ray scattering (SAXS) analyses revealed that all of these polymers were well-segregated based on SAXS measurements at 100 °C, with no evidence of proximity to an order-disorder transition. Most samples formed hexagonal (HEX) or lamellar (LAM) phases, with some persistent HEX/LAM coexistence, with a critical f M-value at the HEX/LAM order-to-order transition that depends on the length and sequence of P blocks. However, the formation of GYR was systematically suppressed by the shaped brush architecture, especially when the longer P block was P 9; this is surprising, given that previously reported MP a diblocks exhibited significant GYR phase windows. Furthermore, despite the low glass transition temperatures of the blocks (T g,M = 69 °C, T g,Pa ≤ -42 °C), there was no evidence of structural refinement over a time scale of hours, indicating very slow ordering kinetics.
The convergence of sustainability and advanced functionality is critical in the design of next-generation biomedical materials. Here, we report a biodegradable microneedle (MN) platform composed of polyurethane (PU) synthesized by the chemical recycling of polylactic acid (PLA). This green strategy upcycles PLA waste to produce a flexible, mechanically robust matrix suitable for transdermal applications. Incorporation of a trace amount (∼0.005 wt %) of delaminated Ti3C2T x MXene imparts photothermal responsiveness under near-infrared (NIR) irradiation, antioxidant capacity (demonstrated using in vitro radical-scavenging assays), and improved mechanical strength. These features enable heat-triggered model drug release and suggest the potential for managing local oxidative stress in wound environments. In vitro assessments confirmed effective skin penetration, photothermal cycling stability, and acceptable cytocompatibility. This proof-of-concept study establishes a sustainable, multifunctional MN platform that integrates circular polymer design with stimuli-responsive performance, supporting future development for advanced transdermal drug delivery applications.
The development of noninvasive diagnostic platforms for biomarker detection in complex biological fluids remains a significant challenge. Herein, we report a biomolecule-inspired, metal-ion-free polymeric fluorescence chemosensor in which polymer architecture governs molecular recognition and photophysical response, enabling ultrasensitive detection of arginine (Arg), a clinically relevant biomarker for metabolic and renal disorders. Based on a coumarin-tyrosine-functionalized polynorbornene synthesized via ring-opening metathesis polymerization (ROMP), the system integrates recognition sites within a well-defined macromolecular framework. UV-vis studies reveal a bathochromic shift (350-442 nm) with an isosbestic point at 392 nm upon Arg binding. Both Poly-Cou-Tyr-Boc and Poly-Cou-Tyr-NH 2 exhibit ratiometric fluorescence behavior in DMSO. The polymeric architecture affords enhanced signal amplification over monomeric analogues, achieving a limit of detection (LOD) of 71.42 nM and 103.64 nM, respectively. Systematic evaluation established artificial saliva as the optimal medium due to negligible matrix interference. In this environment, the probes demonstrated matrix-dependent fluorescence sensing. Poly-Cou-Tyr-Boc maintained ratiometric performance, while the deprotected Poly-Cou-Tyr-NH 2 functioned via high-sensitivity intensity-based quenching at 411 nm. This dual-mode capability yielded exceptional LODs of 33.09 nM and 32.45 nM in saliva, respectively. Mechanistic studies, including 1H NMR titration and Job's plot, confirmed a 1:1 interaction mediated by cooperative hydrogen bonding. This work establishes a structure-property-driven polymer design strategy, providing a versatile metal-ion-free platform for next-generation noninvasive diagnostics and real-time metabolic monitoring.
Safety concerns of flammable liquid electrolytes as well as challenges related to the use of high-capacity anodes, such as silicon-based ones, are among the bottlenecks for achieving next-generation Li-ion batteries. Herein, we synergistically blend poly-(ethylene carbonate) and poly-(ethylene oxide) copolymers with complementary molecular weights and cross-linking densities into membranes with lithium bis-(fluorosulfonyl)-imide (LiFSI) salt concentrated up to 140 mol %. The process leads to membranes without any electrochemical performance-enhancing additive, denoted as additive-free in this work. The thin, mechanically robust, and self-standing cross-linked polymer electrolyte membrane (CP-EM) isused in an all-solid-state battery (ASSB), with scalable LiFePO4 membrane-electrode assembly (LFP-MEA), and a prelithiated silicon oxide-carbon (Li y SiO x C) anode. Electrochemical characterization reveals a CP-EM with a high lithium-ion transference number (t +) of 0.61, a low activation energy (E a) of 0.110 eV, anodic stability exceeding 4.0 V, and a suitable interphase with the lithium metal. The integration of the CP-EM into the proof-of-concept full cell with the LFP-MEA and Li y SiO x is conducted with a practical N/P ratio of 1.16. The full cell delivers an initial reversible capacity of ∼140 mAh g-1 at 70 °C, with an average working voltage of 3.2 V and limited polarization. Despite stability and rate capability still needing further improvements, this study offers a synergic design for blending distinct macromolecular architectures, with a specific balance between segmental flexibility for ion transport and structural integrity. The outcomes demonstrate the practical viability of the integrated MEA in scalable full cells operating at relatively high temperatures.
Physically cross-linked hydrogels formed through noncovalent interactions offer reversible gelation, injectability, and shear-thinning behavior, making them ideal for biomedical applications. Temperature-responsive systems are particularly attractive, as they enable injection as a solution, and at physiological temperature for minimally invasive delivery. Poly-(oligo-(ethylene glycol) methacrylate) (POEGMA) is a promising nonimmunogenic polymer that combines PEG-like hydration and protein resistance with tunable thermal responsiveness that does not bind pre-existing anti-PEG antibodies that are ubiquitous and elicits a minimal antibody response against itself. Here, we show that diblock POEGMA copolymerscomposed solely of short ethylene glycol side chainsspontaneously self-assemble into nanoparticles and form physically cross-linked hydrogels above a controllable transition temperature, without chemical modification. Using fluorescence recovery after photobleaching and video particle tracking nanorheology, we identify a thermally induced transition from dynamically arrested viscoelastic hydrogels to dynamically arrested liquid coacervates. These results establish a new class of single-component, nonimmunogenic POEGMA hydrogels with tunable phase behavior and mechanical properties, offering a versatile platform for localized drug delivery, sustained release, and regenerative medicine.
Conjugated microporous polymers (CMPs) are attractive organic photocatalysts because their porosity, extended pi conjugation, and tunable donor-acceptor (D-A) architectures can promote light harvesting, charge separation, and substrate transport. Herein we report two pyridine-based donor-acceptor CMPs, BTPP-TPA and BTPP-TPT, synthesized through Suzuki coupling of a tetrabrominated pyridine-containing building block (BTPP) with triphenylamine (TPA)- or triphenyltriazine (TPT)-based boronate monomers. Both CMPs exhibit high thermal stability, permanent porosity, broad visible-light absorption, and favorable electronic structures for photocatalytic applications. Notably, the more planar and nitrogen-rich BTPP-TPT framework shows enhanced interfacial charge transport, stronger dye-framework interactions, and superior photocatalytic activity relative to BTPP-TPA. BTPP-TPT delivered adsorption efficiencies of 98.29% for rhodamine B (RhB) and 98.24% for methylene blue (MB) within 90 min and achieved visible-light-driven photodegradation rate constants of 2.6 & times; 10-2 min-1 for RhB and 1.7 & times; 10-2 min-1 for MB. Spectroscopic and electrochemical studies, together with molecular orbital calculations, indicate that D-A polarization and linker planarity govern charge separation and reactive oxygen species generation in these frameworks. This work highlights how molecular-level engineering of pyridine-based CMPs can regulate porosity, electronic structure, and photocatalytic function, providing an effective strategy for metal-free polymer photocatalysts for wastewater remediation.
Structure-function relationships for polymeric gene carriers are derived from crude, heterogeneous mixtures of free polymers and polymer-pDNA complexes (polyplexes). Recognizing that our current understanding of polyplex solution properties may be erroneous, we separated free polymers from crude polyplexes to gain important, previously inaccessible perspectives into polymer-mediated pDNA delivery. Free polymers, the numerically dominant species in crude polyplexes, impose characterization and quality control challenges similar to empty viral capsids and lipid nanoparticles. Polyplexes are frequently formed at large stoichiometric excesses of cationic groups in polymers relative to phosphates in pDNA resulting in nitrogen-to-phosphorus ratios between 5-100. Most polymers exist as "free polymers" in dynamic equilibrium with pDNA-bound polymers. For the first time, we quantified the contributions of free polymers to polyplex solution properties and biological performance. We separated free polymers from polyplexes by applying asymmetrical flow field-flow fractionation (AF4), which removes free polymers under gentle laminar flow, minimizing shear stress and keeping polyplexes intact. While batch light-scattering analysis of unfractionated crude polyplexes severely underestimates polyplex size and pDNA loading by 2-4 & times;, AF4-aided removal of free polymers sharpened measurements by eliminating background light-scattering contributions. Polyplexes with 78% free polymers aggravated inflammatory responses in macrophages by 2-20 & times; compared to polyplexes devoid of free polymers. Removing free polymers depressed transfection efficiency by 50% while improving cell viability by 30%; reintroducing free polymers abrogated these contrasts. By separating and quantifying free polymers using AF4, we corrected systematic biases in structure-function trends gleaned from crude polyplexes. For instance, microstructure-dependent trends in pDNA loading reported in our earlier work originated from differences in free polymer content rather than the polymer microstructure itself. Our study establishes that free polymers skew measurements of polyplex properties and biological performance and offers design guidance to navigate trade-offs between transfection efficiency, immunogenicity, and toxicity.
This study investigates the puncture and tear fracture behavior of isotactic polypropylene (iPP) films with an ultrahigh fraction of continuous and ordered β-transcrystallinity (β-TC), in comparison with α-spherocrystal, α-transcrystallinity, and β-spherocrystal films. In puncture tests, where the loading is applied perpendicular to the film surface, the β-TC film withstood a displacement exceeding 10 mm without rupture, absorbing substantially more energy than the other films. In tear tests, where the loading is applied parallel to the film surface, the β-TC film displayed pronounced ductile tearing characteristics, including significant yielding and strain-hardening, indicative of superior in-plane tear resistance. Quantitative evaluation using the Essential Work of Fracture (EWF) method further revealed that the specific essential work of fracture (we)a measure of intrinsic fracture toughnessreached 38.229 kJ/m2 for the β-TC film, representing an 81.39% enhancement over the β-spherocrystal film. These findings systematically establish a clear correlation between the ordered β-transcrystalline morphology and the multidimensional fracture resistance of iPP films, highlighting a promising strategy for the design of high-performance polymer films.
The miscibility of polymer-resin systems is a key factor for processing behavior and performance of elastomer compounds, yet it is commonly assessed only indirectly. In this work, a quantitative approach for evaluating experimental characterization of the molecular interaction of amorphous polymer filler composites is introduced based on glass transition measurements by differential scanning calorimetry (DSC). Binary mixtures of isoprene rubber (IR) with three distinct biobased resins, a terpene resin, a rosin ester, and a maleic-modified rosin ester, were investigated over the entire composition range. The molecular interaction is expressed by an interaction parameter which reveals stronger repulsive interactions between IR and the rosin ester compared to the other resins of investigation. Mechanical investigation by torque measurements during mixing and transmission electron microscopy (TEM) indicates a correlation between the interaction parameter measured by DSC and the miscibility of the components of the composites.
RNA interference (RNAi) offers a promising approach for vector control in species such as the lone star tick (Amblyomma americanum), but current delivery methods, including microinjection and soaking, are invasive and inefficient for large-scale application. In this work, we developed a series of novel physically cross-linked cationic glycopolymer hydrogels for noninvasive double-stranded RNA (dsRNA) delivery and evaluated their rheological properties, release behavior, and in vivo performance. Rheological characterization demonstrated shear-thinning and self-healing behavior conducive to sprayable applications, while release studies revealed tunable cargo delivery dependent on glycomonomer stereochemistry and cationic content. In vivo studies showed that cationic terpolymer hydrogels successfully traversed the peritrophic membrane and enabled tissue-specific gene silencing, including in ovarian tissue. These findings establish a promising platform for sprayable RNAi delivery and provide a framework for the design of targeted gene delivery systems.
Plasma polymer nanoparticles (pp-NPs) have emerged as linker-free nanocarriers for bioactive cargo and as nanofuels for laser-driven nuclear fusion, yet the structural factors governing their functionality remain poorly understood. Here, pp-NPs were synthesized via plasma polymerization of hexane, cyclohexane, and benzene to determine how monomer structure and specific energy input control radical concentration, hydrogen content, and hierarchical topology. Electron spin resonance and variable-energy positron annihilation lifetime spectroscopy establish that unquenched radical concentrations (1014-1016 spins mg-1) and free-volume size (0.5-0.6 nm) increase from aliphatic to aromatic monomers, whereas free-volume concentration decreases inversely. These trends arise from biradical formation in benzene plasma, steric constraints of aromatic rings, and denser packing caused by reduced hydrogen content, as confirmed by elastic recoil detection analysis. Higher discharge power unexpectedly reduces cross-link density in pp-NPs; statistical network reconstruction reveals that unsaturated carbon bonds reduce the concentration of elastically active network chains more strongly than dehydrogenation increases it. Atomic force microscopy demonstrates that aliphatic monomers yield smoother overall NP surfaces but with a more locally roughened profile (roughness exponent alpha = 0.68), whereas pp-benzene NPs exhibit higher global roughness yet smoother local morphology (alpha = 0.75). Upon deposition, pp-NPs assemble into porous coatings with interparticle voids tunable via NP size (65-560 nm). Together, these findings elucidate how plasma chemistry governs the hierarchical architecture of pp-NPs from subnanometer free volumes to nanoscale surface morphology and mesoscopic interparticle voids, establishing design principles for tailoring radical concentration, hydrogen content, and multiscale porosity for advanced applications.
Stimuli-responsive polymers have endowed soft matter research with numerous applications. Moving beyond classical stimuli like temperature or pH, we introduce an electrochemical approach to control block copolymer aggregation by shifting between bishydrophilic and amphiphilic states. The aqueous solutions of the nonionic-cationic block copolymers poly[N-(3-aminopropyl)methacrylamide]30-b-poly(N,N-dimethylacrylamide)120 (PAPMA30-b-PDMAA120), synthesized via RAFT polymerization, and poly(ethylene oxide)114-b-poly{[2-(methacryloyloxy)ethyl]diisopropylmethylammonium chloride}171 (i.e., PEO114-b-PDPAEMA171 with a quaternized poly(diisopropylaminoethyl methacrylate) block, abbreviated as qPDPAEMA), were investigated for micellization via Dynamic Light Scattering (DLS), Small Angle X-ray Scattering (SAXS), and Cryogenic Transmission Electron Microscopy (cryo-TEM). Both polymers exhibit selective aggregation with hexacyanoferrate species: PAPMA-b-PDMAA forms aggregates specifically in the presence of ferrocyanide ions ([Fe(CN)6]4-), while PEO-b-qPDPAEMA forms micelles with ferricyanide ions ([Fe(CN)6]3-). These polymer systems demonstrate both chemical and electrochemical reversibility, with the combined polymer system allowing selective control over the type of polymer that aggregates by modulating the ferricyanide/ferrocyanide ratio. Furthermore, the pH sensitivity of PAPMA-b-PDMAA allows the disintegration of the micellar state by increasing the pH (electro-)chemically. In total, these results demonstrate full control over the assembly state of complex polymer mixtures by electrochemical means. In addition, it is shown for PEO-b-qPDPAEMA that electrochemical switching as a soft trigger leads to the thermodynamically preferred micelle morphology, while rapid chemical redox leads to kinetically trapped, nonequilibrium micelles. Here, electrochemistry can act as a trigger to transform the trapped micelles toward the thermodynamically stable ones, which can be recycled back to the nonequilibrium micelles. The principle of this electrochemically triggered micellization could represent a significant step toward developing stimuli-sensitive materials for autonomous drug delivery, sensing, or even smart materials within a systems chemistry approach.
