Membrane properties of trisulfonated hydrophilic and partially fluorinated hydrophobic multiblock copolymer
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Polymer Science↗
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Multiblock Copolymer Anion-Exchange Membranes Derived from Vinyl Addition Polynorbornenes
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Selhorst, Ryan↗
Upcycling waste PET into functional multiblock copolymers through controlled macromolecular design
Poly(ethylene terephthalate) (PET) oligomers derived from glycolysis depolymerization were converted into multiblock copolymers through diisocyanate-mediated coupling with dihydroxy-terminated oligomers, enabling precise control over copolymer sequence distribution, connectivity, and mechanical performance. Here, we demonstrate that telechelic PET oligomers isolated directly from depolymerized consumer waste can serve as reactive building blocks for the formation of segmented multiblock copolymers, eliminating the need to revert to monomeric feedstocks. Dihydroxy-terminated PET oligomers (Mw ≈ 8 kg mol−1) were coupled with poly(ethylene oxide) (PEO, Mw ≈ 4 kg mol−1) to form PET-PEO multiblock copolymers with high molar mass (Mw ≈ 160 kg mol−1). We further show that the timing of end-capping reactions provides a key control parameter that governs the competition between chain extension and termination, thereby dictating the resulting multiblock architecture and molecular-weight evolution. Evaluation of their mechanical properties reveals that virgin PET exhibits high modulus (∼3 GPa) and strength (43 MPa) but limited ductility (<10% elongation). In contrast, PET–PEO multiblock copolymers retain comparable tensile strength (44 MPa), albeit while exhibiting dramatically enhanced ductility (>90% elongation), forming tougher materials with efficient stress transfer between the rigid PET domains and the flexible PEO segments. When incorporated into PET/PEO blends at low loadings, the multiblock copolymers serve as effective compatibilizers, yielding materials with an intermediate modulus (1.1–1.2 GPa) and improved elongation compared to uncompatibilized blends. Furthermore, the presence of PEO blocks increases water uptake and gas permeability relative to virgin PET, reflecting the tunability of molecular transport through the copolymeric blocks. To our knowledge, this represents the first report of PET–PEO multiblock copolymers derived from post-consumer PET for gas transport applications. These results demonstrate that multiblock copolymer formation from telechelic PET oligomers provides a versatile platform for tailoring the mechanical and transport behavior of polyester-based materials through controlled macromolecular design and establishes a generalizable strategy for transforming consumer plastic waste into functional segmented polymers without requiring complete depolymerization to monomers.
Watson-Sanders, Shelby [Department of Chemistry, U↗
Polydiallylammonium-Polysulfone Multiblock Copolymers for Moisture-Swing Direct Air Capture of Carbon Dioxide
Polysulfones are an important class of materials for a variety of applications due to their excellent strength and thermal stability. Quaternary ammonium polymers are also useful materials due to their ion exchange properties, and such materials with alkaline counterions have been used to capture carbon dioxide (CO 2 ) from ambient air through a moisture-driven mechanism. Herein, we design sulfone-based multiblock copolymers containing ammonium functionalities and demonstrate their potential for CO 2 capture. Specifically, a series of multiblock copolymers containing both polydiallyldimethylammonium (PDADMA) and polysulfone (PSf) blocks were synthesized. PSf blocks provide mechanical integrity, while the PDADMA blocks enable the direct air capture of CO 2 . Multiblock copolymers were synthesized at high yield, and PDADMA(OH)-PSf copolymer films with good flexibility and strength were formed with IECs of 424 μmol/g (17 mol % PDADMA(OH)), 1407 μmol/g (44 mol % PDADMA(OH)), and 1726 μmol/g (50 mol % PDADMA(OH)). Thermogravimetric analysis was used to determine that all films are thermally stable up to 345 °C. Differential scanning calorimetry revealed that the 17 and 44 mol % functionalized PDADMA(OH)-PSf multiblock copolymers showed one T g at 185 °C and 50 mol % PDADMA(OH)-PSf polymer showed a T g at 183 °C and a second T g at 16 °C. Atomic force microscopy showed that the multiblock polymers exhibit disordered phase separation. Furthermore, the copolymer materials displayed moisture-swing direct air capture of CO 2 , opening up pathways to utilize polymer architecture and chemistry to tailor the properties of promising sorbents.
42 ENGINEERING↗
Chemically Recyclable and Tunable Polyolefin-Like Multiblock Copolymer Adhesives
Adhesives are important in creating multilayer products, such as in packaging and construction. Most current hot-melt adhesives such as poly(ethylene-co-vinyl acetate) (EVA) and polyurethanes lack chemical recyclability and do not easily de-bond, complicating recycling. Here, we achieved tunable adhesive properties of chemically recyclable polyolefin-like multiblock copolymers through regulating the incorporation of crystalline hard blocks, amorphous soft blocks, and ester content highlighted by adhesive strengths up to 6.80 MPa. We further demonstrated applications of these adhesives in multi-layer films and showed that the adhesives can be readily de-bonded, recovered, and chemically recycled. Overall, this study into structure-property relationships, including effects of crystallinity, soft-block incorporation, and ester content of the multiblock copolymers on adhesive properties, has resulted in a modular hot-melt adhesive platform that exhibits chemical recyclability for virgin-quality adhesive re-generation, reprocessability for repeated reuse of the recovered adhesive, and tunability for designing adhesives with a wide range of low to high (up to ~80% stronger than EVA) adhesion strengths.
36 MATERIALS SCIENCE↗
Assembly of Disordered Cocontinuous Morphologies by Multiblock Copolymers with Random Block Sequence and Length Dispersity
Among the wide variety of nanostructures accessible by self-assembly of block copolymers, cocontinuous morphologies are of great interest for separations, catalysis, sensing, and energy storage due to their ability to integrate distinct properties of the constituent polymers. Furthermore, we investigate the tendency to form disordered cocontinuous phases of multiblock copolymers (MBCs) with random block sequence and length dispersity prepared by step-growth polymerization of pre-made telechelic polymers, specifically using thiol-Michael addition between diacrylate functionalized polystyrene (PS) and poly (D,L - lactide) (PLA) chains and a small molecule dithiol. In the phase diagram so established, disordered cocontinuous nanostructures occupy a wide window (≈ 25 % vol) at a modest segregation strength of χN = 15, close to the critical value for microphase separation. At a higher segregation strength of χN = 30, only a moderately wide (≈ 10 vol %) cocontinuous window is found, with MBCs instead tending to form ordered nanostructures. Although the breadth of the cocontinuous widow is less than that found in prior work on analogous randomly end-linked copolymer networks (RECNs), the MBC architecture offers offsetting advantages in terms of solution and melt processability.
36 MATERIALS SCIENCE↗
Autoxidized Oleic Acid Bifunctional Macro Peroxide Initiators for Free Radical and Condensation Polymerization. Synthesis and Characterization of Multiblock Copolymers
Autoxidation of unsaturated fatty acids gives fatty acid macroperoxide initiators containing two functionalities which can lead to free radical and condensation polymerizations in a single pot. The oleic acid macroperoxide initiator obtained by ecofriendly autoxidation (Pole4m) was used in both the free radical polymerization of styrene and the condensation polymerization with amine-terminated polyethylene glycol (PEGNH2) to obtain triblock branched graft copolymers. The narrow molar masses of the poly oleic acid-g-styrene (PoleS) and poly oleic acid-g-styrene-g-PEG (PoSG) graft copolymers were successfully obtained. The inclusion of oleic acid decreased the glass transition temperature of the polystyrene segment because of the plasticizing effect of oleic acid. In addition, a mechanical property of the copolymer was improved when compared with the pure PS. Structural characterization, morphology of the fracture surface, micelle formation, thermal analysis and molar masses of the obtained products were also evaluated.
36 MATERIALS SCIENCE↗
Synthesis and Properties of Poly(vinyl chloride)- b -polyethylene Multiblock Copolymers through the Hydrodechlorination of PVC with Silylium Ions
Polymer compatibilizers stabilize the interface between two immiscible polymers to allow for a material that improves properties for additional use. Chlorinated polyethylene (CPE) is a common compatibilizer, yet there does not exist a synthetic pathway either from monomers or via the functionalization of polyethylene (PE) to yield a polymer that has a controlled chlorine amount and primary structure along the polymer chain. Herein, we report a series of novel block copolymers of poly(vinyl chloride) (PVC) and PE, synthesized through selective hydrodechlorination of PVC. Contrary to CPE, the full range of chlorination can be obtained and the block number can be altered. Interfacial adhesion studies reveal samples with competitive compatibilization of PVC/polyolefin elastomer blends (POE). In conclusion, this method shows that post-polymerization modification can be a strategic top-down synthesis to achieve high performance polymers.
Wood, Zachary A. [Univ. of Southern California, Lo↗
Simulations of swollen, self-assembled single-ion-conducting multiblock copolymers
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Vigil, Daniel Lee↗
High-performance multiblock PEMs containing a highly acidic fluorinated-hydrophilic domain for water electrolysis
The present paper describes the design and evaluation of novel hydrophilic–hydrophobic poly(arylene ether sulfone) (PAES) multiblock copolymers for their synergistic effects upon transport properties and their potential use in proton exchange membrane water electrolysis. The multiblock copolymers are prepared via a coupling reaction between (i) a hydrophilic segment consisting of a disulfonated quinone fluorinated biphenyl group that contains fluorine moieties next to the sulfonated groups to increase the acidity, and (ii) hydrophobic segments composed of non-sulfonated biphenyl sulfone to provide dimensional stability. Two different lengths (molecular weights; 5k and 10k, where k represents 10 3 g mol -1 ) of hydrophobic segments are used to investigate the effects of the membrane properties compared with those of Nafion® and PAES random copolymer (i.e., BPSH40). Atomic force microscopy images of the BPSH40 and multiblock membranes are shown to agree closely with a mesoscale simulation, thus confirming the importance of the morphological effect upon the transport properties. Furthermore, the multiblock copolymer with a higher proportion of hydrophilic segments (10 k–5k) was shown to provide enhanced performance (3.41 A cm -2 at 1.9 V) compared to the multiblock copolymer with equal proportions of hydrophilic and hydrophobic segments (10 k–10 k) due to the greater continuity of nano-sized ionic channels.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
A simple route to prepare supramolecular block copolymers using telechelic polystyrene/polydimethyls
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Obando, Alejandro Guillen↗
Simple Monomers for Precise Polymer Functionalization During Ring-Opening Metathesis Polymerization
Controlling the monomer sequence of synthetic polymers is a grand challenge in polymer science. Conventional sequence control has been achieved in dispersed polymers by exploiting the kinetic tendencies of monomers and their order of addition. While the sequence of blocks in multiblock copolymers can be readily tuned using sequential addition of monomers (SAM), control over the sequence distribution is eroded as the targeted block size approaches a single monomer unit (i.e., X n ~ 1) due to the stochastic nature of chain-growth reactions. Thus, unique monomers are needed to ensure precise single additions. Herein, we investigate common classes of cyclic olefin monomers for ring-opening metathesis polymerization (ROMP) to identify monomers for single unit addition during sequential monomer addition synthesis. Through careful analysis of polymerization kinetics, we find that easily synthesized oxanorbornene imide monomers are suitable for single-addition reactions. With the identified monomers, we demonstrate the synthesis of multiblock copolymers containing up to three precise functionalization sites and singly cross-linked four-armed star copolymers. In conclusion, we envision that expanded kinetic analyses of monomer reactivities in ROMP reactions will enable novel polymer synthesis capabilities such as the autonomous synthesis of sequence-defined polymers or one-shot multiblock copolymer syntheses.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Probing the interface structure of block copolymer compatibilizers in semicrystalline polymer blends
Abstract The use of block copolymers to compatibilize immiscible plastics is an important strategy for upcycling municipal plastic wastes. Multiblock copolymers (MBCPs) have been proven to be more effective compatibilizers than di‐ and tri‐block copolymers. Herein, we probe the interface structure of an effective multiblock copolymer compatibilizer and compare that with an ineffective triblock copolymer (TBCP). The interface activity of the compatibilizers is understood through a combination of small‐angle neutron and x‐ray scatterings (SANS and SAXS), by using deuterated homopolymer matrix and protonated compatibilizers. SANS analysis suggests that the MBCP forms a thicker interface layer (7–9 nm) than the TBCP (0–4 nm). In addition, SANS data seems to point to a stronger tendency for the MBCP to locate at the interface. Both factors contribute to its effectiveness at compatibilizing immiscible homopolymers.
36 MATERIALS SCIENCE↗
Recent advances in thermoplastic elastomers from living polymerizations: Macromolecular architectures and supramolecular chemistry
Thermoplastic elastomers (TPEs) have found use in a wide range of applications, such as adhesives, elastomers, coatings, fibers, and in additive manufacturing techniques such as 3D printing. Despite their omnipresence, the need for advanced TPEs with adaptive properties is continuously growing. Along with a brief historical introduction, this review introduces an overview of typical structure-property relationships for various TPEs and discusses the design principles of TPEs from a synthetic chemistry perspective. Recent advances in TPEs with different macromolecular architectures, including linear ABA triblock copolymers, ABC triblock terpolymers, multiblock copolymers, star copolymers, graft copolymers, bottlebrush polymers, and hyperbranched polymers are reviewed. Service temperatures and mechanical properties of the different materials are compared in each section. Incorporating various supramolecular interactions into different macromolecular architectures as a means to further extend the range of TPE applications is also reported on. Further opportunities for TPE research in both academia and industry are proposed as perspectives.
36 MATERIALS SCIENCE↗
Bottom-Up Simulation, Reconstruction, and Quantification of Macromolecule Sequences from Experimental Polymerizations
Motivated by the canonical sequence–structure–function paradigm, tools to characterize chemical patterning in natural biomacromolecules, from proteins to nucleic acids, have grown exponentially in recent years. However, analogous strategies for synthetic macromolecules remain in nascent stages, complicated by sequence polydispersity and analytical limitations. To address this, we have developed a comprehensive and open-source Python package, PRISM (polymer rate insights and sequence modeling), an end-to-end workflow that provides a path from experimental kinetics measurements to quantitative and qualitative metrics for describing chemical patterning in stochastic polymers. First, a numerical integration strategy was constructed to simulate and fit experimental data from reversible addition–fragmentation chain transfer (RAFT) polymerization kinetics, enabling the facile estimation of relevant reactivity ratios. These ratios were then used in a mechanism-specific stochastic kinetic simulation strategy to simulate sequence ensembles corresponding to model systems spanning experimental copolymers, classes of statistical polymers (e.g., alternating, block, and gradient), and multiblock copolymers. Lastly, inspired by sequence homology metrics from bioinformatics, we introduce visualization strategies and quantitative metrics to facilitate comparisons of different sequence ensembles. As the sequence–structure–function paradigm becomes increasingly central in de novo design of synthetic macromolecules, this toolkit provides a first step toward accurate and representative sequence description and featurization.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Simulation-guided analysis of resonant soft X-ray scattering for determining the microstructure of triblock copolymers
Resonant soft X-ray scattering (RSoXS) probes structure with chemical sensitivity that is useful for determining the morphology of multiblock copolymers. However, the hyperspectral scattering data produced by this technique can be challenging to interpret. Here, in this study, we use computational scattering simulations to extract the microstructure of a model triblock copolymer from the energy-dependent scattering from RSoXS. An ABC triblock terpolymer formed from poly(4-methylcaprolactone) (P4MCL), poly(2,2,2-trifluoroethylacrylate) (PTFEA), and poly (dodecylacrylate) (PDDA), P4MCL-block-PTFEA-block-PDDA, was synthesized as the model triblock system. Through quantitative evaluation of simulated scattering data from a physics-informed set of candidate structure models against experimental RSoXS data, we find the best agreement with hexagonally packed core–shell cylinders. This result is also consistent with electron-density reconstruction from hard X-ray scattering data evaluated against electron-density maps generated with the same model set. These results demonstrate the utility of simulation-guided scattering analysis to study complex microstructures that are challenging to image by microscopy.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Mesophase Structure-Enabled Electrostrictive Property in Nylon-12-Based Poly(ether- block -amide) Copolymers
In this work, to search for alternative electrostrictive polymers and to understand the underlying mechanism, the structure-ferroelectric/electrostrictive property relationship for nylon-12-based poly(ether-b-amide) multiblock copolymers (PEBAX) is investigated. Two PEBAX samples are studied, namely, P6333 and P7033 with 37 and 25 mol.% of soft poly(tetramethylene oxide) (PTMO) blocks, respectively. In both samples, poorly hydrogen-bonded mesophase facilitates electric field-induced ferroelectric switching. Meanwhile, the longitudinal electrostrictive strain (S 1 )–electric field (E) loops are obtained at 2 Hz. Different from conventional poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)]-based terpolymers, uniaxially stretched nylon-12-based PEBAX samples exhibit negative S 1 , that is, shrinking rather than elongation in the longitudinal direction. Additionally, this is attributed to the unique conformation transformation of nylon-12 crystals during ferroelectric switching. Namely, at a zero electric field, crystalline nylon-12 chains adopt a more or less antiparallel arrangement of amide groups. Upon high-field poling, ferroelectric domains are enforced with more twisted chains adopting a parallel arrangement of amide groups. Meanwhile, extensional S 1 is observed for P6333 at electric fields above 150 MV m -1 . This is attributed to the elongation of the amorphous phases (i.e., amorphous nylon-12 and PTMO). Therefore, competition between shrinking S 1 from mesomorphic nylon-12 crystals (i.e., nanoactuation) and elongational S 1 from amorphous phases determines the ultimate electrostriction behavior in stretched PEBAX films.
36 MATERIALS SCIENCE↗
Hydrolysis-Induced Morphology Evolution of Linear and Bottlebrush Block Copolymers in Thin Films with Acid Vapor or Photoacid Generators
The self-assembly of high-χ low-N block copolymers (BCPs) can give patterns with sub-10 nm full pitch, serving as a promising alternative to photolithographic methods. Here, in this work, we synthesized poly(solketal methacrylate)-block-polystyrene copolymers, PSM-b-PS, with various volume ratios of the two blocks. After hydrolysis of the PSM block into poly(glycerol monomethacrylate), PGM, the BCPs had both lamellar and cylindrical microdomain morphologies in the bulk phase and in thin films. In addition to our previously developed solid-state hydrolysis strategy involving trifluoroacetic acid vapor, we developed a new photoinduced solid-state hydrolysis using photoacid generators, PAGs, embedded within the polymer films. After exposure to UV followed by a postexposure baking or solvent vapor annealing, the BCPs transitioned from the disordered, phase-mixed state into laterally ordered cylindrical patterns. In comparison to linear BCPs that rely on a random copolymer layer to modify interfacial interactions with the substrate to promote an orientation of the microdomains normal to the interface, we found that the microdomains in bottlebrush multiblock copolymers oriented normal to the interface absent substrate modification due to the chain architecture.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗