Comb Copolymers Research Articles

Molecular design of antifouling ultrafiltration membranes via copolymerization of bactericidal and hydrophilic polymers

Membrane fouling is still a significant obstacle to applying polyvinylidene fluoride (PVDF) ultrafiltration membranes. We developed bactericidal and hydrophilic comb copolymers to address this issue by introducing quaternary ammonium compounds (QAC) and sulfobetaine methacrylate (SBMA) onto PVDF powder. Utilizing atom transfer radical polymerization, we synthesized a series of polymer brushes by adjusting the QAC and SBMA functional monomers ratio. These polymer brushes were then employed to fabricate modified membranes featuring diverse alkyl chain lengths and hydrophilic layers. All modified membranes exhibited antibacterial and anti-adhesion properties. Increasing the SBMA monomer ratio resulted in reduced membrane pore size, a smoother membrane surface, and enhanced hydrophilicity. This balanced approach synergistically integrates “defensive” and “offensive” strategies, adjusting polymer proportions to confer dual functionality of hydrophilicity and bactericidal action in ultrafiltration membranes. Notably, the functionalized PVDF powder with copolymer chains exhibited a high inhibition efficiency of 100% against E. coli and 52.0% against E. faecalis, and the optimized membranes have an impressive performance of effectively preventing bacteria adhesion and inactivating attached bacteria. Dynamic filtration experiments further revealed the superior anti-biofouling capabilities of the modified membrane. Furthermore, the membrane containing 50% SBMA and 50% QAC exhibited a 69.5% improvement in anti-organic performance compared to those with only QAC. Our study presents a straightforward and efficient approach for designing antifouling PVDF membranes, showing great promise for wastewater treatment applications.

Force-induced desorption of copolymeric comb polymers

We investigate a lattice model of comb copolymers that can adsorb at a surface and that are subject to a force causing desorption. The teeth (the comb’s side chains) and the backbone of the comb are chemically distinct and can interact differently with the surface. That is, the strength of the surface interaction can be different for the monomers in the teeth and in the backbone. We consider several cases including (i) the uniform case where the number of teeth is fixed and the lengths of the branches in the backbone and the lengths of the teeth are all identical, (ii) the case where the teeth are short compared to the branches in the backbone, (iii) the situation where the teeth are long compared to the backbone, and (iv) the case where the number of teeth approaches infinity. We obtain expressions for the free energies in the thermodynamic limit in terms of those for self-avoiding walks and discuss the nature of the phase diagrams of the model.

The effect of comb length on the in vitro and in vivo properties of self-assembled poly(oligoethylene glycol methacrylate)-based block copolymer nanoparticles.

Comb copolymer analogues of poly(lactic acid)-polyethylene glycol block copolymers (PLA-b-PEG) offer potential to overcome the inherent chemistry and stability limitations of their linear block copolymer counterparts. Herein, we examine the differences between P(L)LA10K-b-PEG10K and linear-comb copolymer analogues thereof in which the linear PEG block is replaced by poly(oligo(ethylene glycol) methacrylate) (POEGMA) blocks with different side chain (comb) lengths but the same overall molecular weight. P(L)LA10K-b-POEGMA47510K and P(L)LA10K-b-POEGMA200010K block copolymers were synthesized via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) and fabricated into self-assembled nanoparticles using flash nanoprecipitation via confined impinging jet mixing. Linear-comb copolymer analogues based on PLA-b-POEGMA yielded smaller but still well-controlled nanoparticle sizes (88 ± 2 nm and 114 ± 1 nm respectively compared to 159 ± 2 nm for P(L)LA10K-b-PEG10K nanoparticles) that exhibited improved colloidal stability relative to linear copolymer-based nanoparticles over a 15 day incubation period while maintaining comparably high cytocompatibility, although the comb copolymer analogues had somewhat lower loading capacity for doxorubicin hydrochloride. Cell spheroid studies showed that the linear-comb copolymers promoted enhanced tumor transport and thus cell killing compared to conventional linear block copolymers. In vivo studies showed all NP types could passively accumulate within implanted CT26 tumors but with different accumulation profiles, with P(L)LA10K-b-POEGMA200010K NPs showing continuous accumulation throughout the full 24 h monitoring period whereas tumor accumulation of P(L)LA10K-b-POEGMA47510K NPs was significant only between 8 h and 24 h. Overall, the linear-comb copolymer analogues exhibited superior stability, biodistribution, spheroid penetration, and inherent tunability over linear NP counterparts.

The Use of High‐Temperature Semi‐Batch Radical Polymerization to Synthesize Acrylate Based Macromonomers and Structured Copolymers

AbstractA high‐temperature starved‐feed semi‐batch operating policy is developed to produce p(acrylates) with high macromonomer content, taking advantage of side reactions inherent to acrylate radical polymerization. This operating strategy results in significantly higher macromonomer content for the polymerization of isobornyl acrylate (iBoA) versus n‐butyl acrylate (BA) under identical operating conditions. This is because steric hindrance favors fragmentation (i.e., terminal double bond (TDB) formation) over addition (i.e., short‐chain or long‐chain branch (LCB) formation), thus increasing the p(iBoA) TDB content and decreasing polymer dispersity. The p(iBoA) macromonomer solution serves as an excellent addition‐fragmentation agent to polymerize a second monomer in a single pot process controlled by sequential feeding, as demonstrates by the production of iBoA‐BA block and comb copolymer structures at different temperatures and macromonomer concentrations. The incorporation of the p(iBoA) macromonomer into a copolymer product is verified by various techniques, including polymer fractionation followed by TDB, composition, and molar mass analyses. Reaction temperature plays a key role in determining whether a blocky versus comb copolymer structure is produced. The ability to synthesize block and comb copolymers by radical polymerization without a mediating agent offers the potential to efficiently produce structured copolymers for industrial applications.

Rearrangement and morphological transition of DNA on adsorbent templates of hydrocarbon/fluorocarbon phase‐separated monolayers

AbstractA phase‐separated template prepared from a mixed monolayer of fluorinated long‐chain s‐triazine derivatives and comb copolymers containing s‐triazine rings was morphologically controlled by DNA adsorption. The adsorbed morphology of DNA was formed through a morphological transition process at the air/water interface rather than by maintaining the shape of the phase‐separated template. Dot‐like domains, circular domains, centrally protruding domains, network morphologies, and even co‐continuous surface morphologies of DNA were obtained. The phase‐separated monolayer used as a template depends on the mixed ratio of the fluorocarbon and hydrocarbon copolymer components, the copolymerization ratio of the hydrocarbon copolymers, and the chain length of the fluorinated long‐chain s‐triazine derivative, and various morphological transitions occur. The DNA introduced into the sub‐phase was selectively adsorbed onto the s‐triazine ring‐containing comb copolymer, and the adsorbed DNA assembly exhibited a morphological transition based on concerted interactions. Furthermore, by utilizing a fluorescent probe molecule, evidence of DNA morphogenesis itself was supported by its emission/quenching behavior.Highlights Morphological control of the DNA assembly was attained. Immobilization of DNA assemblies on phase‐separated templates was achieved. Preparation of patterned templates was realized by copolymers a fluorinated derivative. Adsorption of DNA to the diamino‐s‐triazine ring was achieved by hydrogen bonding. A rearrangement of the DNA assemblies on the template was achieved.

Linear, Star, Comb, and Ring Crystallizable Multiblock Copolymers Investigated by Molecular Dynamics Simulations

Linear, Star, Comb, and Ring Crystallizable Multiblock Copolymers Investigated by Molecular Dynamics Simulations

Controlling the various phase-separated patterns in mixed monolayers of non-amphiphilic fluorinated derivatives and hydrogenated comb copolymers

Mixed monolayers were prepared on the water surface of non-amphiphilic fluorinated derivatives, as well as hydrocarbon-based comb copolymers, whose intermolecular interactions could be tuned using a copolymerization method. The phase-separated morphologies of the monolayers could also be controlled. Diamino-s-triazine rings, which were critical in morphology formation, were introduced into the hydrophilic groups of the comb copolymers for the phase-separated patterning. The phase-separation pattern was precisely controlled using various parameters, such as the chain length of the fluorinated derivatives, composition of the comb copolymers, mixing ratio, subphase temperature, and surface pressure. The obtained sea-island phase-separated patterns were classified into domain-like, circular, non-circular linear, donut-like, and centrally protruding circular domain morphologies. At 35 °C, a new nucleation phenomenon was observed inside the donut-shaped pattern that had developed through coagulation. During the phase separation of the current system, crystalline regularity was achieved in the fluorinated sea region around the domain, which was generally a continuous phase.

Polymer-Infiltrated Metal–Organic Frameworks for Thin-Film Composite Mixed-Matrix Membranes with High Gas Separation Properties

Thin-film composite mixed-matrix membranes (TFC-MMMs) have potential applications in practical gas separation processes because of their high permeance (gas flux) and gas selectivity. In this study, we fabricated a high-performance TFC-MMM based on a rubbery comb copolymer, i.e., poly(2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl] ethyl methacrylate)-co-poly(oxyethylene methacrylate) (PBE), and metal-organic framework MOF-808 nanoparticles. The rubbery copolymer penetrates through the pores of MOF-808, thereby tuning the pore size. In addition, the rubbery copolymer forms a defect-free interfacial morphology with polymer-infiltrated MOF-808 nanoparticles. Consequently, TFC-MMMs (thickness = 350 nm) can be successfully prepared even with a high loading of MOF-808. As polymer-infiltrated MOF is incorporated into the polymer matrix, the PBE/MOF-808 membrane exhibits a significantly higher CO2 permeance (1069 GPU) and CO2/N2 selectivity (52.7) than that of the pristine PBE membrane (CO2 permeance = 431 GPU and CO2/N2 selectivity = 36.2). Therefore, the approach considered in this study is suitable for fabricating high-performance thin-film composite membranes via polymer infiltration into MOF pores.

Porous thin films with hierarchical structures formed by self-assembly of zwitterionic comb copolymers

Zwitterions exhibit high dipole moments and strong intra- and inter-molecular interactions. As a result, amphiphilic copolymers with zwitterionic repeat units easily self-assemble. Here, we explore the wide range of self-assembled morphologies formed by zwitterionic comb-shaped copolymers (ZCCs) comprising a hydrophobic backbone and zwitterionic side-chains. We study the effect of polymer structure, architecture, and film preparation method on self-assembled morphology. We synthesized ZCCs with varying zwitterionic side chain density and length, and applied each ZCC as a thin film on glass substrates using different methods. We compared the morphology of these films with ZCCs films coated on a porous substrate by non-solvent induced phase separation, creating mechanically supported thin films (MSTFs) and comparing them with films on non-porous substrates. The porous support led to distinct changes in film morphology, creating hierarchical features including ∼17 nm spherical micelles along with larger nanopores (∼85 nm). This feature size could be tuned using a zwitterionic homopolymer additive. MSTFs exhibited significant changes in water permeance and morphology upon exposure to saline solutions, known to stimulate expansion of the zwitterionic side-chains. These results demonstrate the wide range of morphologies accessible by this comb copolymer family and document the significant effect of a porous support on the film formation process.

Thin-film composite mixed-matrix membrane with irregular micron-sized UTSA-16 for outstanding gas separation performance

Low-cost, micron-sized particles still pose a barrier to their use in thin-film composite mixed-matrix membranes (TFC-MMMs) owing to their poor interfacial contact with the polymer matrix. Also, the particles are too large to be fabricated into the submicron-thick membranes. Herein, we report high-performing, TFC-MMMs based on a CO2-philic comb copolymer, poly (tetrahydrofurfuryl methacrylate)–co–poly (poly (oxyethylene methacrylate)) (PTO), and an irregular, micron-sized, CO2-selective metal-organic framework (MOF), UTSA-16. The PTO comb copolymer matrix exhibited excellent film-forming ability, adhesion properties and showed a good gas separating performance. The PTO comb copolymer also enhanced the dispersibility of UTSA-16 in an environment-friendly solvent mixture (i.e., ethanol/water), which did not adversely damage the underlying porous polymeric support. Despite the micron-scale particle size of UTSA-16, PTO copolymer completely covered the surface of UTSA-16 via strong interactions without any deep pore infiltration and exhibited excellent interfacial contact properties. Consequently, defect-free TFC-MMMs with a polymer thickness of 300 nm were successfully prepared on the porous support. The TFC-MMM with 10% filler loading exhibited excellent CO2 permeance and selectivity, i.e., CO2 permeance of 1070 GPU, CO2/N2 selectivity of 41.0, CO2/CH4 selectivity of 17.2, outperforming the TFC-MMMs prepared with commercially available Pebax. All PTO-based MMMs, with the exception of the low content of UTSA-16 (5%), exceeded the gas separation performance required for post-combustion CO2 capture process.

Multifunctional, bicontinuous, flexible comb copolymer electrolyte for solid-state supercapacitors

Solid electrolytes with high safety, good flexibility, and wide potential windows have attracted significant interest as alternatives to conventional liquid electrolytes, which have the disadvantages of flammability and leakage. Herein, we report a high-performance polymer electrolyte comprising a poly(isobornyl methacrylate)-co-poly(ethylene glycol) methyl ether methacrylate (PIBMA-co-PEGMA) (PIBEG) amphiphilic comb copolymer for solid-state supercapacitors (SCs). The PIBEG comb copolymer was synthesized via facile, inexpensive, and scalable free radical polymerization, followed by the incorporation of an ionic liquid (IL) to fabricate an ion-conducting flexible polymer electrolyte. Owing to the microphase-separated structure, the PIBEG films showed homogeneity and good flexibility up to 85 wt% of IL loading. The PIBEG/IL electrolytes had a bicontinuous, worm-like nanostructure with an ionic conductivity of 4.35 mS cm−1. The solid SC with PIBEG/IL electrolytes exhibited a specific capacitance of 48.6 F/g and an energy density of 37.12 Wh kg−1 at a power density of 1174 W kg−1, which are among the highest values reported for flexible solid SCs with conventional activated carbon electrodes. Furthermore, SCs could be fabricated without the use of separators or adhesives due to the multifunctional properties of PIBEG/IL electrolytes, including strong adhesion, high conductivity, and good mechanical strength.

Ferroelectric electroluminescent comb copolymer for single-material self-powered displays

Ferroelectric polymers have recently been applied in human-connected electronics as pressure (touch)-sensing materials to develop high-performance electronic skin and tactile sensing memory. Here, we report an organic synthetic route for developing a polymer possessing both ferroelectric and electroluminescent properties from which a self-powered pliable display can be readily implemented. The synthetic route involves reversible addition-fragmentation transfer-mediated graft copolymerization of poly(vinylidene fluoride) (PVDF) onto a polyfluorene (PFO) backbone, which results in a comb-like copolymer architecture composed of ferroelectric side chains (PVDFs) tethered to a light-emitting main chain (PFO). The resultant thin comb copolymer film, equipped with hardly integrable three natures (i.e., ferro- and piezoelectricity, luminescence, pliability), exhibits excellent light emission under alternating current and self-powering attributes upon mechanical deformation. This multifunctional polymer, where various properties including ferroelectricity and electroluminescence are imparted in molecular-level precision, envisions its use in a wide range of fields such as emerging self-powered interactive displays. • Synthesis of comb copolymer consisting of PFO backbone grafted with PVDF polymer • Copolymer with synchronous ferroelectric and electroluminescent properties • Development of polymer light-emitting diode with self-powered piezoelectricity Kim et al. demonstrate a ferroelectric-polymer-grafted electroluminescent comb copolymer that simultaneously exhibits ferroelectricity, photoluminescence, and electroluminescence. The ferroelectric and light-emitting film can be readily used in flexible polymer light-emitting diodes and piezoelectric nanogenerators via solution processing, making it a promising candidate for the development of wearable human-interactive self-powered photoelectronics.

Insight into the Structure of a Comb Copolymer–Surfactant Coacervate from Dynamic Measurements by DOSY NMR and Neutron Spin Echo Spectroscopy

Insight into the Structure of a Comb Copolymer–Surfactant Coacervate from Dynamic Measurements by DOSY NMR and Neutron Spin Echo Spectroscopy

DNA patterning utilizing mixed monolayer template by phase separation between hydrocarbons and fluorocarbons and evaluation of second-order structural maintenance ability

Adsorption of DNA molecules on mixed phase-separated monolayers composed of a hydrocarbon-containing comb copolymer with an s-triazine ring and a fluorinated s-triazine derivative and their fluorescence emission behavior were investigated. DNA molecules derived from salmon testes were selectively adsorbed only on the diamino-s-triazine ring of the hydrogenated copolymer in the monolayer from the subphase. A mixed monolayer of a hydrocarbon-based comb copolymer and an s-triazine derivative with fluorocarbons exhibited phase separation behavior on water surfaces and indicated expansion behavior, reflecting interactions on the subphase containing DNA molecules. The phase-separated morphology changed depending on the mixing ratio of the hydrogenated copolymer and fluorinated s-triazine derivative. After DNA adsorption, the height of the domain formed by the hydrocarbon chain was selectively increased. In addition, because the DNA molecules adsorbed on the phase-separated template film maintain their fluorescence emission ability, the second-order structure, which is the origin of the emission ability, was evaluated using circular dichroism spectroscopy. The phase-separated, template-adsorbed DNA molecules maintained the same positive Cotton effect as in solution and were predicted to retain exquisite and delicate steric structure, leading to functional occurrence.

Loop and Bridge Conformations of ABA Triblock Comb Copolymers: A Conformational Assessment for Molecular Composites

We computationally investigate the conformational behavior, “bridging” chain, between different the phase-separated domains vs “looping” chain on the same domain, for two chain architectures of ABA triblock copolymers, one with a linear architecture (L-TBC) and the other with comb architecture (C-TBC) at various segregation regimes using dissipative particle dynamics (DPD) simulations. The power-law relation between the bridge fraction () and the interaction parameter () for C-TBC is found to be in the vicinity of the order-disorder transition (), indicating a drastic conversion from the bridge to the loop conformation. When further increases, the bridge-loop conversions slow down to have the power law, , approaching the theoretical power law predicted in the strong segregation limit. The conformational assessment conducted in the present study can provide a strategy of designing optimal material and processing conditions for triblock copolymer either with linear or comb architecture to be used for thermoplastic elastomer or molecular nanocomposites.

Structure regulation and influence of comb copolymers as pour point depressants on low temperature fluidity of diesel fuel

Adding pour point depressants (PPDs) is a simple and efficient method to remediate the low temperature fluidity of diesel, however, the depressive effects of these polymeric PPDs are always affected by their molecular structure and polarity. In this work, to obtain high-efficiency PPDs for diesel, a series of comb copolymers of tetradecyl methacrylate-benzalacetone (C14MC-BAE), tetradecyl methacrylate-methyl cinnamate (C14MC-MCA) and tetradecyl methacrylate-ethyl 3-benzoylacrylate (C14MC-EBLA) were synthesized by the regulation of molecular structure. The depressive effects of these copolymers on the cold filter plugging point (CFPP) and solid point (SP) of diesel were studied and compared with that in previous reports. Results showed monomers with carbonyl group closer to benzene ring in side chain have better inhibition. As the mole ratio of monomer up to 9:1, these PPDs had the best depressive effect on CFPP and SP of diesel. Thereinto, C14MC-EBLA (9:1) at 2000 ppm decreased the CFPP and SP of diesel by 12 °C and 15 °C, respectively. Furthermore, the morphology and crystallization behavior of wax crystals in diesel before and after adding PPDs were analyzed by polarizing optical microscope, differential scanning calorimeter and viscosity-temperature curves.

Self-Consistent Field Theory Predicts Universal Phase Behavior for Linear, Comb, and Bottlebrush Diblock Copolymers

Self-Consistent Field Theory Predicts Universal Phase Behavior for Linear, Comb, and Bottlebrush Diblock Copolymers

In situ crosslinking of polyoxometalate-polymer nanocomposites for robust high-temperature proton exchange membranes

The most practical high-temperature proton exchange membranes (PEMs) are phosphoric acid (PA)-doped polymer electrolytes. However, due to the plasticizing effect of PA, it is a challenge to address the trade-off between the proton conductivity and the mechanical performance of these materials. Here, we report an effective strategy to fabricate robust high-temperature PEMs based on the in situ electrostatic crosslinking of polyoxometalates and polymers. A comb copolymer poly(ether-ether-ketone)-grafted-poly(2-ethyl-2-oxazoline) (PGE) with transformable side chains was synthesized and complexed with H3PW12O40 (PW) by electrostatic self-assembly, forming PGE/PW nanocomposite membranes with bicontinuous nanostructures. After a subsequent PA-treatment of these membranes, high-temperature PEMs of PGE/PW/PA ternary nanocomposites were obtained, in which the in situ electrostatic crosslinking effect between PW and PGE side chains was generated in the hydrophilic domains of the bicontinuous structures. The microphase separation structure and the electrostatic crosslinking feature endow the PGE/PW/PA membranes with excellent anhydrous proton conductive ability while retaining high mechanical performance. The membranes show a high proton conductivity of 42.5 mS/cm at 150 °C and a high tensile strength of 13 MPa. Our strategy can pave a new route based on electrostatic control to design nanostructured polymer electrolytes.

Highly CO-Selective Mixed-Matrix membranes incorporated with Ag Nanoparticle-Impregnated MIL-101 Metal–Organic frameworks

The significance of carbon monoxide (CO) as an invaluable starting material for chemical industries necessitates comprehensive analysis of membrane-based CO separation and recovery. In this regard, highly CO-selective mixed-matrix membranes (MMMs) based on dual carriers [Ag+ ions and Ag nanoparticle (NP)-impregnated MIL-101 (Ag@MIL-101)] were fabricated herein for CO separation. A highly adhesive comb copolymer [poly(glycidyl methacrylate-co-poly(oxyethylene methacrylate); PGMA-co-POEM; PGO] plays a pivotal role as a di-functional matrix in anchoring Ag+ ions and uniformly dispersing Ag@MIL-101 particles, resulting in excellent interfacial properties. An optimal CO-separation performance is achieved at an Ag@MIL-101 loading of 10 wt% (CO permeance of 30.7 GPU and CO/N2 selectivity of 11.8), which is superior compared to that of membranes with single Ag+ ions. This study elucidates the synergistic CO transport effect of the positively charged AgNP-impregnated MOFs and Ag+ ions through the fabricated membranes, and proposes a novel concept of “accelerated transport.” The separation mechanism behind the high CO capture property is delineated using molecular dynamic simulation through morphology and energetic analyses.

3D finite element simulation model of a chemiresistor gas sensor based on ZnO and graft comb copolymer integrated in a gas chamber

3D finite element simulation model of a chemiresistor gas sensor based on ZnO and graft comb copolymer integrated in a gas chamber