Side-chain Polymers Research Articles

Passivation of Iodine Vacancies in Perovskite Photodetectors by Oxygen Functional Groups in the Main and Side Chains of Alcohol Polymers

Passivation of Iodine Vacancies in Perovskite Photodetectors by Oxygen Functional Groups in the Main and Side Chains of Alcohol Polymers

Sulfonium-based polymethacrylamides for antimicrobial use: influence of the structure and composition.

We are facing a shortage of new antibiotics to fight against increasingly resistant bacteria. As an alternative to conventional small molecule antibiotics, antimicrobial polymers (AMPs) have great potential. These polymers contain cationic and hydrophobic groups and disrupt bacterial cell membranes through a combination of electrostatic and hydrophobic interactions. While most examples focus on ammonium-based cations, sulfonium groups are recently emerging to broaden the scope of polymeric therapeutics. Here, main-chain sulfonium polymers exhibit good antimicrobial activity. In contrast, the potential of side-chain sulfonium polymers remains less explored with structure-activity relationships still being limited. To address this limitation, we thoroughly investigated key factors influencing antimicrobial activity in side-chain sulfonium-based AMPs. For this, we combined sulfonium cations with different hydrophobic (aliphatic/aromatic) and hydrophilic polyethylene glycol (PEG) groups to create a library of polymers with comparable chain lengths. For all compositions, we additionally examined the position of cationic and hydrophobic groups on the polymer backbone, i.e., we systematically compared same center and different center structures. Bactericidal tests against Gram-positive and Gram-negative bacteria suggest that same center polymers are more active than different center polymers of similar clog P. Ultimately, sulfonium-based AMPs show superior bactericidal activity and selectivity when compared to their quaternary ammonium cationic analogues.

Self-Assembly of Amorphous 2D Polymer Nanodiscs with Tuneable Size, pH-Responsive Degradation and Controlled Drug Release.

Amphiphilic bottlebrush block copolymers (BBCs) with tadpole-like, coil-rod architecture can be used to self-assemble into functional polymer nanodiscs directly in water. The hydrophobic segments of the BBC were tuned via the ratio of ethoxy-ethyl glycidyl ether (EE) to tetrahydropyranyl glycidyl ether (TP) within the grafted polymer sidechains. In turn, this variation controlled the sizes, pH-responsiveness, and drug loading capacity of the self-assembled nanodiscs. Notably, as EE exhibited faster hydrolysis than TP, the nanodiscs featured variable degradation rates under mild acidic conditions, aiding small molecule release and time-dependent and complete degradation of discs into fully water-soluble copolymers. The nanodiscs demonstrated biocompatibility and cellular uptake by breast cancer cells, underscoring their potential development into drug delivery systems.

Conjugated core-shell bottlebrush polymers that exhibit crystallization-driven self-assembly.

Bottlebrush polymers are complex architectures with densely grafted polymer side chains along polymeric backbones. The dense and conformationally extended chains in bottlebrush polymers give rise to unique properties, including low chain entanglement, low critical aggregation concentrations, and elastomeric properties in the bulk phase. Conjugated polymers have garnered attention as lightweight, processible, and flexible semi-conducting materials. They are promising candidates in electronic devices and sensors, but their optoelectronic properties depend on adequate polymer ordering, π-π interactions, and crystallization. Crystallization-driven self-assembly of conjugated polymers has become a prominent method to optimize properties including band energies, redox potentials, and exciton diffusion and transport. Much progress has been made in controlled block copolymer self-assembly, but despite their promising properties, reports of conjugated bottlebrushes have been limited, and their self-assembly is relatively unexplored. For the first time, we report the synthesis of conjugated core-shell bottlebrush polymers. These materials contain poly(3-hexylthiophene) (P3HT) and poly(ethylene glycol) (PEG) in either core or shell position. We demonstrate that the use of P3HT as a crystallizable conjugated polymer and PEG as a colloidally stabilizing and disaggregating block facilitates their self-assembly into a number of unique crystalline morphologies with longer conjugation lengths and lower exciton bandwidths relative to analogous diblock copolymers. These include intramolecularly self-assembled segregated bottlebrush polymers, short nanofibers formed by end-on-end stacking of bottlebrush molecules, extremely long >20 μm nanofibers formed exclusively by end-on-end stacking, and >15 μm nanoribbons formed from both end-on-end and side-by-side stacking of bottlebrush polymers.

Effect of Acrylate Emulsion on the Mechanical and Microscopic Properties of Straw Fiber-Reinforced Cement-Magnesium Slag Stabilized Soil.

In order to investigate the mechanism of mechanical performance enhancement and the curing mechanisms of acrylate emulsion (AE) in cement and magnesium slag (MS) composite-stabilized soil (AE-C-M), this study has conducted a comprehensive analysis of the compressive strength and microstructural characteristics of AE-C-M stabilized soil. The results show that the addition of AE significantly improves the compressive strength of the stabilized soil. When the AE content is 0.4%, the cement content is 3%, and the magnesium slag content is 3% (AE4-C3M3), the strength of the formula reaches 4.21 MPa, which meets the requirements of heavy traffic load conditions in the construction of high-speed or main road base layers. Some reactive groups on the polymer side chains (-COOH) engage in bridging with Ca2+ and RCOO- to form a chemically bonded interpenetrating network structure, thereby enabling the acrylate emulsion to enhance the water damage resistance of the specimens. The notable improvement in strength is attributed to the film-forming and solidifying actions of AE, the binding and filling effects of C-S-H gel, and the reinforcing effect of straw fibers. FT-IR and TG-DSC analysis reveals the presence of polar electrostatic interactions between AE and the soil matrix. AE enhances the bonding among soil particles and facilitates the attachment of C-S-H gel onto the surfaces of the straw fibers, thereby increasing the strength and toughness of the material. The application of MS in conjunction with straw fibers within polymer-modified stabilized soil serves to promote the recycling of waste materials, thereby providing an environmentally friendly solution for the engineering application of solid waste.

Enhanced photocatalytic performance in seawater of donor-acceptor type conjugated polymers through introduction of alkoxy groups in the side chain.

Previous studies have demonstrated that the donor (D)-acceptor (A) structure enables conjugated polymers (CPs) to effectively inhibit charge recombination, reduce exciton binding energy to a minimum, and broaden the light absorption spectrum, ultimately enhancing photocatalytic activity. Besides, side chain engineering is an effective approach to enhance photocatalytic performance by regulating surface chemistry and energy band structure of CPs. Herein, three D-A type CPs, namely TPD-T, TPD-MOT and TPD-DOT, were designed and synthesized using thieno[3,4-c]pyrrole-4,6-dione (TPD) as A units and thiophene with different alkyl/alkoxy groups side chain (as 3-octylthiophene (T), 3-methoxythiophene (MOT) and 3,4-ethylenedioxythiophene (DOT)) as D units, via an atom- and step-economic CH/CH cross-coupling polycondensation. The photocatalytic hydrogen production performance of these polymers driven by visible light was systematically evaluated in pure water and natural seawater. The results show that the hydrogen evolution rates (HERs) of the as-synthesized CPs in pure water and natural seawater significantly increased by 5 and 7 times, respectively, when the number of alkoxy groups on the side chain of polymers increased from 0 to 2. In particular, HERs of three polymers in natural seawater are distinctly better than that in pure water. Further, the steady-state photoluminescence (PL), time-resolved fluorescence decay, and electrochemical impedance spectroscopy (EIS) studies combined with density functional theory (DFT) simulations were carried out to figure out the possible mechanism of the enhanced photocatalytic performance of CPs by side chain engineering. This work indicates that side chain engineering contributes significantly to determine the photocatalytic activity of D-A polymers-based photocatalysts, and could serve as guidelines for organic photocatalysts with highly efficient hydrogen evolution performance.

Redox-Active Metal-Organic Framework As an Anode-Active Material for Rechargeable Air Batteries

[Introduction] Rechargeable batteries for the storage of electrical energy are required for the introduction of renewable energy and compact electronic devices for the sustainable society.[1] Although lithium-ion batteries currently dominate the market, rechargeable metal–air batteries with very high energy densities have been attracting attention due to increasing power consumption and demand for low environmental burden. They are composed of oxygen from air as the cathode-active material, metal as the anode-active material and a strong alkaline solution as the electrolyte. They have the advantage of high energy density and low environmental burden due to the use of oxygen as the cathode-active material. While primary Zn–air batteries are commercialized, rechargeable metal–air batteries are under investigation due to their low cycle performance caused by dendrites and metal oxides formed on the metal anode, which leads to disposal of anode-active materials. In addition, strong basic electrolytes are used due to their high ionic conductivity, and the carbonate clogging by carbon dioxide in the air is also a problem. Therefore, rechargeable air batteries, which consist of acid or neutral electrolyte and anode-active materials which is recyclable and do not form dendrites or metal oxides, are required. Organic redox molecules, which are reversibly redox-active organic compounds, are composed of earth-abundant and relatively available building blocks (C, H, N, O, and S), and their functions can be tuned by molecular design, which has attracted attention as new electrode-active materials. We have previously reported that rechargeable polymer–air batteries using an organic redox polymer with organic redox molecules in the side chain of polymer as the anode-active material and acidic aqueous solution as the electrolyte charged and discharged without the formation of dendrites or carbonates.[2] However, organic materials suffer from low durability, and organic redox materials with structural stability in the electrolyte have been required. In the current work, we focused on UiO-66, a metal-organic framework with structural stability in acid and base electrolyte, and synthesized UiO-66-(OH2) with 1,4-dihydroxybenzene, an organic redox molecule as a linker, which undergoes a reversible redox reaction even in acid electrolytes. An anode-active material composed of UiO-66-(OH2) did not form dendrites or metal oxides in H2SO4 aqueous electrolyte (pH 1) and exhibited charge storage with high cycle stability. A rechargeable acidic MOF–air battery was demonstrated for the first time. After use, UiO-66-(OH2) electrode was facilely decomposed and separated to the original raw chemicals by NH4HCO3 aqueous solution.[Results and Discussion] We synthesized UiO-66-(OH2) from zirconium(IV) chloride and 2,5-dihydroxyterephthalic acid by microwave irradiation. UiO-66-(OH2) was coated on a glassy carbon plate in the presence of single-walled carbon nanotube as the conductive additive. The UiO-66-(OH2) electrode exhibited charging-discharging curves of a plateau voltage at 0.2 V, and the ratio of discharging vs. charging capacity (i.e. coulombic efficiency) were nearly 96%. The high capacity of the UiO-66-(OH2) electrode suggested that almost all of the -OH moieties contributed to charge storage. Even after 300 cycles, UiO-66-(OH2) electrode exhibited high cycle performance, which was relatively robust compared to other n-type redox materials for rechargeable aqueous air batteries. These results demonstrated that UiO-66-(OH2) has high cycle stability as an anode-active material for rechargeable acidic MOF-air batteries. A rechargeable acidic MOF-air battery was fabricated with a UiO-66-(OH2), Pt/C, and H2SO4 aqueous electrolyte (pH 1) as the anode material, cathode material, and electrolyte, respectively. The coulombic efficiencies of the battery were nearly 97%, demonstrating the reversible charge storage property of the cell. The high capacity for the anode suggested that almost all of the -OH moieties contributed to charge storage. Even after 100 charging-discharging cycles, the battery kept the high discharging capacity even at a rapid discharging. These results demonstrated the long-life ability of the rechargeable acidic MOF-air battery. UiO-66-(OH2) electrode in the battery was facilely decomposed and separated to the original raw chemicals by NH4HCO3 aqueous solution after charging and discharging.[Conclusions] We synthesized UiO-66-(OH2), which is stable in aqueous electrolyte, and applied it to an anode-active material. The rechargeable acidic MOF-air battery exhibited high cycle performance without the formation of dendrites or carbonates. In addition, we successfully recycled UiO-66-(OH2) electrode after charging and discharging. The current work presented a first step for developing electrode materials for the future energy storage.[References][1] J. Kim, Y. Kim, J. Yoo, G. Kwon, K. Kang et al., Nat. Rev. Mater. , 8, 54–70, 2023.[2] K. Oka, S. Furukawa, S. Murao, H. Nishide, K. Oyaizu et al., Chem. Commun. , 56, 4055–4058, 2020. Figure 1

Effects of Polymer Side Chains on Ion Transport Properties of Gel Electrolytes Containing High Concentration Li Salt Solution

Highly concentrated Li salt electrolyte solutions have attracted attention recently due to the unique physicochemical and electrochemical properties.1 Recently, our group reported that highly concentrated Li salt/sulfolane electrolytes exhibit Li+ ion hopping conduction mechanism.2 Gel electrolytes, which incorporate liquid electrolytes within polymer network generally maintain ion transport properties derived from liquid electrolytes. The gelation of liquid electrolytes can prevent the leakage of liquids and improve the safety of batteries. However, certain gel electrolytes containing high concentration Li salt solution have been reported that the ion transport properties can be affected by the participation of the polymer matrix in the solvation structure.3 In this study, we focused on the effects of polymer side chains on ion transport properties of gels. We prepared novel gel electrolytes using polymers with different side chains as a polymer matrix containing high concentration Li salt/sulfolane solutions. Gel electrolytes incorporating lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) and sulfolane (SL) at 1:3 molar ratio, which exhibits a high Li+ ion transference number (t Li+ ), were prepared by free radical polymerization using four types of methacrylate monomers (methyl methacrylate: MMA, propyl methacrylate: PMA, 2,2,3,3-tetrafluoropropyl methacrylate: TFPMA, diethylene glycol monomethyl ether methacrylate: DEGMA). Ionic conductivity and of PMMA gel were comparable to those of PPMA gel with extended alkyl side chains, while in PDEGMA gel with multiple coordination sites for Li+ showed lower t Li+ because Li+ ions were trapped by the ether moiety of the side chain. On the other hand, PTFPMA gel with partially fluorinated propyl side chains showed a higher t Li+ . The self-diffusion coefficients of Li+, TFSA−, and SL in PTFPMA gel measured with pulsed field gradient (PFG) NMR suggested lower diffusivity of TFSA− compared to that in PPMA gel. Moreover, 19F NMR revealed that the signal derived from TFSA− shifted to downfield side in PPMA gel and upfield shift in PTFPMA gel compared to that in the liquid electrolyte of [LiTFSA]/[SL] =1:3, indicating a change of solvation structure due to the polymer side chain. Finally, we demonstrated rate capability tests for gel electrolytes with LiCoO2/Li cells and found that the cell with PTFPMA gel having high t Li+ exhibited better rate performance than one with PPMA gel. Acknowledgements This study was partially supported by Japan Science and Technology Agency (JST) GteX Program (Grant No. JPMJGX23S0) and JSPS KAKENHI (Grant No. 22H00340) from the Japan Society for the Promotion of Science (JSPS). References Yamada and A. Yamada, Review—Superconcentrated Electrolytes for Lithium Batteries, J. Electrochem. Soc., 2015, 162, A2406–A2423.Dokko, D. Watanabe, Y. Ugata, M. L. Thomas, S. Tsuzuki, W. Shinoda, K. Hashimoto, K. Ueno, Y. Umebayashi and M. Watanabe, Direct Evidence for Li Ion Hopping Conduction in Highly Concentrated Sulfolane-Based Liquid Electrolytes, J. Phys. Chem. B, 2018, 122, 10736–10745.Tasaki, Y. Ugata, K. Hashimoto, H. Kokubo, K. Ueno, M. Watanabe and K. Dokko, Tetra-arm poly(ethylene glycol) gels with highly concentrated sulfolane-based electrolytes exhibiting high Li-ion transference numbers, Phys. Chem. Chem. Phys., 2023, 25, 17793–17797.

Gel Polymer Electrolytes Composed of Highly Concentrated Li Salt/Sulfolane Electrolytes and Homogeneous Polymer Network Having Weakly Coordinating Ability

Lithium-ion batteries (LIBs) use flammable organic electrolytes, and there are issues of ignition and leakage of liquid electrolytes. Sulfolane solvent is a non-flammable solvent. We previously reported that the sulfolane-based highly concentrated electrolytes exhibit unique transport properties and high Li+ ion transference numbers. 1) Gelation of liquid electrolyte is useful in preventing leakage and improves the safety of LIBs. Conventional gel polymer electrolytes (GPEs) have low mechanical reliability due to the structural defects such as loop chains and dangling chains. The mechanical toughness of GPE depends on the homogeneity of the polymer network. To achieve good mechanical toughness of GPE, the use of tetra-arm poly(ethylene glycol) (Tetra-PEG) has been proposed.2) The end-coupling reaction of two symmetrical tetra-PEGs can form homogeneous network structure, and tetra-PEG gels exhibit good mechanical toughness.In this work, we synthesized tetra-arm poly(2,2,3,3-tetrafluoropropyl acrylate) (Tetra-PTFPA), and GPEs composed of a sulfolane-based highly Li salt-concentrated electrolyte and tetra-PTFPA. Tetra-PTFPA was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using a tetrafunctional chain transfer agent in THF solvent. This polymerization solution was mixed with a highly concentrated electrolyte, LiN(SO2CF3)2 (LiTFSA) : sulfolane (SL) = 1:3 (molar ratio), then the THF was removed. Then, GPE with a uniform network structure were prepared by adding 1,3-propanediyl diacrylate (PDA) and further RAFT polymerization of both ends of PDA to tetra-PTFPA in the electrolyte to crosslink the different tetra-polymers. A self-standing GPE membrane could be prepared by RAFT polymerization at a polymer concentration of 20 wt%, while self-standing membrane could not be obtained through free radical polymerization at the same crosslinking density. This suggests that the homogeneous network structure in the tetra-PTFPA gel was effective in improving the mechanical reliability of GPE. The Li ion transference number (t Li+) of the tetra-PTFPA gel was evaluated by DC polarization and determined to be 0.64. This value is higher than t Li+ of the mother liquid electrolyte [LiTFSA]/[SL] =1/3 (t Li+ = 0.55). This is probably due to the interaction between TFSA anion and the acidic protons surrounded by fluorine atoms in the polymer side chains of tetra-PTFPA.TFSA anions are assumed to be trapped by polymer side chains in the gel, while Li+ ion less interact with the side chains. This results in a higher transference number of Li+ in the gel electrolytes compared to that in the mother liquid electrolyte. Further results including mechanical and ion transport properties of the tetra-PTFPA gel will be presented. Acknowledgements This study was partially supported by Japan Science and Technology Agency (JST) GteX Program (Grant No. JPMJGX23S0) and JSPS KAKENHI (Grant No. 22H00340) from the Japan Society for the Promotion of Science (JSPS).References1) Dokko K., et al, J. Phys. Chem. B, 2018, 122, 10736-10745.2) Sakai T., et al, Macromolecules, 2008, 41, 5379–5384.

Exploring the Relationship between Ion Diffusion and Molecular Structure of Gel Polymer Electrolytes Using NMR Spectroscopy

Lithium rechargeable batteries are widely used as energy sources for portable electronic devices, automobile, and wearable electronics. However, concerns regarding fire hazards have prompted efforts to transition from liquid to solid electrolytes. Gel polymer electrolytes (GPEs) have emerged as promising alternatives for enhancing the safety of lithium batteries. The ion conduction mechanism in GPEs can be conceptualized in two distinct modes: a liquid-like mechanism and a solid-like mechanism. We focus on the investigation of the liquid-like mechanism, which relies on polymer segmental motion. Various factors can influence ionic conduction of gel polymer electrolytes such as the structure of the sidechain, interaction between sidechain and ionic species etc. We utilize PFG NMR and nuclear relaxation time measurements to explore the correlation between the ionic motion and the structure of polymers and ionic liquids. Chain length of polymer sidechain will be varied and structurally isomeric ionic liquids will be utilized. We will demonstrate that NMR spectroscopy is a good indicator to examine the dynamics of the gel polymer electrolyte. Understanding of the structure-dynamics relation from our study will serve as a design principle to develop new gel polymer electrolyte with desired properties.

Luminescent Radical Polymers.

Organic radicals are gaining significant interest in luminescent materials due to their unique properties, which present unprecedented opportunities for innovation across various fields, from display technology to biomedical applications. However, addressing challenges related to stability and low fluorescence efficiency is crucial to unlocking their full potential for practical applications. Polymerization has emerged as an effective strategy to enhance intra- and interchain through-space interactions, enabling the creation of stable luminescent radicals with excellent processing and multifunctional properties. This concept emphasizes the strategic use of polymerization in designing and synthesizing stable main-chain and side-chain radical polymers. This approach not only broadens the scope of stable radicals but also improves their luminescence properties as photofunctional materials.

Synthesis of Side-Chain Liquid Crystalline Polyacrylates with Bridged Stilbene Mesogens.

In recent years, π-conjugated liquid crystalline molecules with optoelectronic functionalities have garnered considerable attention, and integrating these molecules into side-chain liquid crystalline polymers (SCLCPs) holds potential for developing devices that are operational near room temperature. However, it is difficult to design SCLCPs with excellent processability because liquid crystalline mesogens are rigid rods, have low solubility in organic solvents, and have a high isotropization temperature. Recently, we developed near-room-temperature π-conjugated nematic liquid crystals based on "bridged stilbene". In this work, we synthesized a polyacrylate SCLCP incorporating a bridged stilbene that exhibited a nematic phase near room temperature and could maintain liquid crystallinity for more than three months. We conducted a thorough phase structure analysis and evaluated the optical properties. The birefringence values of the resulting polymers were higher than those of the corresponding monomers because of the enhanced order parameters due to the polymer effect. In addition, the synthesized polymers inherited mesogen-derived AIE properties, with high quantum yields (Φfl = 0.14-0.35) in the solid state. It is noteworthy that the maximum fluorescence wavelength exhibited a redshift of greater than 27 nm as a consequence of film formation. Thus, several unique characteristics of the SCLCPs are unattainable with small molecular systems.

Metal-Coordinated, Dual-Crosslinked PIM Polymer Membranes for Upgraded CO2 Separation: Aging and Plasticization Resistance.

The practical use of polymers of intrinsic microporosity (PIMs) in CO2 separation is often hindered by their moderate selectivity, performance instability over time, and pressure constraints. To address these limitations, a straightforward approach is presented to enhance the CO2 separation capability of PIM-1 by incorporating metal ions into uniformly hydrolyzed PIM-1 (cPIM). This dual linking strategy, achieved via ionic and coordination bonding of metal ions with the polymeric side chains including ─COOH and ─CONH2, restructures the polymer, disrupting hydrogen bonds between cPIM chains and creating active sites for CO2 via π-complexation. This modification enhances gas permeability while maintaining high selectivity. The optimized zinc-coordinated membrane achieves an impressive CO2 permeability of ≈2,500 Barrer with CO2/N2 and CO2/CH4 selectivities of 27.1 and 23, respectively, outperforming pristine cPIM (700 Barrer; CO2/N2=27; CO2/CH4=19). Notably, this performance surpasses the 2008 Robeson upper-bound limits for both gas pairs. Additionally, the metal-coordinated membranes exhibit remarkable long-term stability, resisting aging effects for up to 20 days and maintaining anti-plasticization properties at pressures up to 20 bar. These dual-crosslinked membranes demonstrate promising potential for mixed gas separation, indicating their suitability for real-world industrial applications.

Exciting Novel Polyaspartates: Design, Synthesis, and Photo-Responsive Behavior in Solution and Lyotropic Liquid Crystalline Phase Upon Irradiation with Visible Light.

Many polypeptides form stable, helical secondary structures enabling the formation of lyotropic liquid crystalline (LLC) phases. Contrary to the well-studied polyglutamate, their counterparts based on polyaspartates exhibit a much lower helix inversion barrier. Therefore, the helix sense is not solely dictated by the chirality of the amino acid used, but additionally by the nature and conformation of the polymer sidechain. In this work, polymers responsive to irradiation with visible light are designed achieving conformational transitions from helix-to-coil and helix-to-helix. The synthesis and the application as LLC mesogens of several (co-)polyaspartates bearing ortho-fluorinated azobenzene (FAB) as a photochromic group are presented. Many of the obtained polymers undergo changes in their secondary structure upon E-Z-isomerization of the FAB-containing sidechain. Of special interest are copolymers that exhibit photo-responsive helix inversion without loss of their helical secondary structure. These copolymers form stable LLC phases in helicogenic solvents, where the effect of photo-switching on the macroscopic behavior is studied by NMR spectroscopy. Especially, the irradiation of the different LLC phases of the helix inversion polymers displays a change in the LLC order experienced by the solvent. These peculiar properties are promising for future applications as photo-responsive alignment media for structure elucidation in NMR.

Synthesis and Optimization of Ethylenediamine-Based Zwitterion on Polymer Side Chain for Recognizing Narrow Tumorous pH Windows.

Polyzwitterions that show the alternation of net charge in response to external stimuli have attracted great attention as a new class of surface-polymers on nanomedicines. However, the correlation between their detailed molecular structures and expression of antifouling properties under physiological condition remain controversial. Herein, we synthesized a series of ethylenediamine-based polyzwitterions with carboxy groups/sulfonic groups and ethylene, propylene, and butylene spacers as potential surface-polymers for nanomedicines, allowing sensitive recognition of tumor acidic environments (pH = 6.5-5.5). Then, we evaluated their structure-based characteristics, including pH-dependent cellular uptakes and intracellular distributions. Additionally, the role of conformation stability, i.e., Gibbs free energy changes, was to induce an intramolecular electrostatic interaction in the zwitterionic moieties. These results highlight the practicality of fine-tuning the design of zwitterionic moieties on polymers for the future development of nanomedicines that can recognize the narrow pH window in tumor acidic environments.

Controlling Crystal Orientation in Films of Conjugated Polymers by Tuning the Surface Energy.

It has been a long-term goal to understand the molecular orientation in films of conjugated polymers, which is crucial to their efficient exploitation. Here, we show that the surface energies determine the crystal orientation in films of model conjugated polymers, substituted polythiophenes crystallized on substrates. We systematically increase the surface energy of edge-on crystals formed at the vacuum interface by attaching polar groups to the ends of the polymer side chains. This suppresses crystallization at the vacuum interface, resulting in a uniform face-on crystal orientation induced by the graphene substrate in polythiophene films as thick as 200 nm, which is relevant for devices. Surprisingly, face-on crystal orientation is attained in the modified polythiophenes crystallized even on amorphous surfaces. Furthermore, for the samples with still competing interfacial interactions, the crystal orientation can be switched in the same sample, depending on the crystallization conditions. Thus, we report a fundamental understanding and control of the equilibrium crystal orientation in films of conjugated polymers.

Designing methacrylic anhydride-based hydrogels for 3D bioprinting

Methacrylic anhydride-based hydrogels, derived by introducing methacryloyl groups to various polymer side chains, are promising bioinks for 3D printing in medical applications. These hydrogels combine the inherent biocompatibility and therapeutic benefits of their parent polymers with the unique photocrosslinking properties conferred by the methacryloyl groups, allowing the precise control over their mechanical properties through light-curing parameters. Using three-dimensional (3D) biological compression, these hydrogels serve as bioinks for producing scaffolds with optimal porosity, facilitating cell adhesion, proliferation, and differentiation. This technology enables the precise spatial distribution of bioactive substances, offering targeted therapeutic treatment and controlled release. This review delved into recent advancements in bioprinting technologies, outlined the preparation of methacrylic anhydride-based bioinks, and summarized factors influencing the resulting biological and mechanical properties of bioscaffolds. Additionally, the properties and applications of methylpropionic anhydride-based hydrogels in various medical fields were discussed, addressing current limitations and future challenges in integrating these hydrogels with 3D bioprinting for clinical applications.

Bis-cationic crosslinked anion exchange membranes based on carbazole-containing polyaromatics with excellent ionic conductivity for alkaline water electrolysis

As the core component in anion exchange membrane water electrolyser (AEMWE), anion exchange membrane (AEM) directly determines the electrolysis performance and long-term durability of AEMWE. Herein, we synthesized novel poly(carbazole-p-terphenylpiperidine) (PCTP-x) copolymers and then prepared a series of bis-cationic cross-linked AEMs (QPCTP-x-bpip) using the Menshutkin reaction between the cross-linker 4,4′-trimethylenebis(1-methylpiperidine) and the alkyl bromide on the polymer side chains. For comparison, non-crosslinked AEMs containing alkylpiperidinium side chains (QPCTP-x-pip) were prepared via a grafting reaction of alkyl bromide with 1-methylpiperidine. The bis-cationic crosslinked membrane exhibited high hydroxide conductivity of 190.0 mS cm−1, and demonstrated outstanding alkaline stability in a 1 M KOH solution at 80 °C, retaining more than 90 % of the initial hydroxide conductivity and tensile strength after 2200 h alkaline treatment. Meanwhile, the flexural carbazole backbone enhanced polymer solubility, enabling the utilization of QPCTP-20-pip as an anion exchange ionomer (AEI) in AEMWE. For the water electrolysis testing, AEMWE employing QPCTP-20-bpip as the AEM and QPCTP-20-pip as the AEI exhibited excellent performance, achieving a current density of 2910 mA cm−2 at 2.0 V using a 1 M KOH feed at 80℃. Moreover, the voltage increase during the in-situ durability test over 200 h was a mere 0.65 mV/h, demonstrating its promising potential for AEMWE applications.

Side-chain-induced changes in aminated chitosan: Insights from molecular dynamics simulations

Chitosan is a functional polymer with diverse applications in biomedicine, agriculture, water treatment, and beyond. Via derivatization of pristine chitosan, its functionality can be tailored to desired applications, e.g. immobilization of biomolecules. Here, we performed molecular dynamics simulations of three aminated chitosan polymers, where one, two, and three long-distanced side chains have been incorporated. These polymers have been previously synthesized and their properties were investigated experimentally, however, the observed dependencies could not be fully explained on the molecular level. Here, we develop a computational protocol for the simulation of functionalized chitosan polymers and perform advanced analysis of their conformational states, intramolecular interactions, and water binding. We demonstrate that intra- and intermolecular forces, especially hydrogen bonds induced by polymer side chain modifications, modulate dihedral angle conformational states of the polymer backbone and interactions with water. We explain the role of the chemical composition of the functionalized chitosans in their tendency to collapse and reveal the key role of the protonation of the amino group near the polymer backbone on the reduction of polymer collapse. We demonstrate that specific binding of water molecules, especially the intermediate water, is more pronounced in the polymer exhibiting such an amino group.

Stereoisomeric separation and chiral recognition mechanism study of star cyclodextrin polymer as the chiral stationary phase

BackgroundAs the derivatives of cyclodextrin (CD), cyclodextrin polymers (CDPs) effectively increase the concentration of CD units and construct supramolecular structures with unique stereoselectivity by the structure design. CDPs have shown significant potential in chiral separation, however, the process of stereoselective interactions on chiral stationary phases (CSPs) and the specific contribution of intermolecular forces are still a challenge issue. A comprehensive understanding of the chiral recognition mechanism of CDPs will help to optimize chiral separation conditions and design new CSPs. ResultsThe star CDP with a supermolecular structure was synthesized by grafting β-CD onto the external 6-position hydroxyl groups using β-CD as the parent nucleus. The enhanced host-guest recognition ability of CD supramolecular polymer structure provided better inclusion interaction and increased chiral recognition of the isomers. The Star-CD CSP with star CDP as a chiral ligand performed satisfactory stereoisomer separation ability with the separation factor (α) up to 2.0 for various quinoline alkaloid isomers and 1.89 for catechins. To elucidate its chiral separation mechanism, molecular docking was used to construct the three-dimensional visual models of the binding sites and the contribution of non-covalent interactions between Star-CD CSP and quinoline alkaloid isomers. In addition, the formation sites of non-covalent interactions on the CD monomers of the polymer side chains were confirmed from the actual geometric structure by analyzing the NMR chemical shift changes before and after the formation of complexes between Star-CD polymers and isomers. Combined with the mutual evidence of molecular simulation and chiral NMR, the specific recognition mechanism of selector-selectand complexes was comprehensively expounded. SignificanceThe multi-mode CSP based on cyclodextrin supramolecular structure provides new ideas for the stereoisomeric separation of complex chiral components with multiple chiral centers in natural products. Not limited to the macroscopic performance of the chromatographic separation, molecular docking explored the theoretical model of chiral recognition from the molecular level. The chiral NMR analysis confirmed the credibility of the model from the geometry structure, and then the recognition mechanism of multi-mode CSP was fully elaborated combining the above three aspects.