Hydrophilic Copolymers Research Articles

Highly aqueously stable C60-polymer nanoparticles with excellent photodynamic property for potential cancer treatment.

Fullerenes are a class of carbon nanomaterials that find a wide range of applications in biomedical fields, especially for photodynamic cancer therapy because of its photosensitive effect. However, hydrophobic fullerenes can only be dispersed in organic solvents which hinders their biomedical applications. Here, we report a facile method to prepare highly water-dispersible fullerene (C60)-polymer nanoparticles with hydrodynamic sizes of 50-70nm. Hydrophilic random copolymers containing different ratios of polyethylene glycol methyl ether methacrylate and 2-aminoethylmethacrylamide were synthesized for conjugating with C60 molecules through efficient nucleophilic Michael addition reaction between amine groups from hydrophilic polymer and carbon-carbon double bonds from C60. As a result, the amphiphilic C60-polymer conjugates could be well dispersed and nano-assembled in water with a C60 concentration as high as 7.8mg/mL, demonstrating a significant improvement for the solubility of C60 in an aqueous system. Owing to the high C60 content, the C60-polymer nanoparticles showed a strong photodynamic therapy effect on human lung cancer cells (A549) under light irradiation (450nm) in both 2D cell culture and 3D spheroid culture, while demonstrating ignorable cytotoxicity under dark. This highly efficient and convenient method to prepare water-dispersible C60-polymer conjugates may have a great impact on the future biomedical applications of fullerenes.

Redox-responsive biodegradable dendronized polymers: A side-chain modulation based fabrication of drug delivery vehicles

Among various nanomedicine platforms, stimuli-responsive biodegradable polymeric micelles offer a viable approach to address challenges in cancer therapy. Herein, we report the fabrication of redox-responsive micellar aggregates based on an amphiphilic dendron-polymer conjugate. In particular, acid-degradable hydrophobic polyester dendrons are attached as side chain moieties through a disulfide linkage on a hydrophilic copolymer. Polymers containing three generations of dendrons are synthesized using the thiol-disulfide exchange reaction and utilized to obtain micellar aggregates. The stability of the obtained aggregates, drug loading, and release characteristics in neutral, acidic, and redox environments were investigated. It was established that micelles are efficiently internalized by cells, and the highest level of cytotoxicity was observed for MDA-MB-231 breast cancer carcinoma cells under a reducing environment.

Hard–Soft Segment Synergism Binder Facilitates the Implementation of Practical SiC600 Electrodes

AbstractAs an emerging anode material for commercialization, the silicon (or SiOx)/graphite composite (SiC) anode faces bottlenecks such as large volume expansion and short cycle lifespan, which hinder its commercial implementation process. To remove these limitations, a mussel byssal thread‐inspired hard–soft segment synergism binder (denoted as PCH‐CR) is presented based on an in situ ester cross‐linking reaction between a hydrophilic copolymer of sodium 2‐carboxyethylacrylate and N‐(2‐hydroxyethyl)acrylamide as the hard segment with an oleophilic elastomer carboxylic styrene butadiene rubber as the soft segment. This synergetic hard–soft segment binder design can evidently improve the polymer topological structure entropy, thus obtaining enhanced mechanical and adhesive properties. By virtue of these strengths, the as‐prepared SiC600 (600 mAh g−1 at 0.1 C) electrodes can apparently suppress electrode volume expansion, and subsequently maintain high structural integrity and interfacial stability during cycling. As a result, the as‐prepared SiC600 electrode at a limited PCH‐CR binder dosage achieves unprecedented cycling and rate performance in coin and home‐made soft package cells. These results promise great potential for the as‐developed binder for practical SiC600 electrode applications. This work marks a new milestone in developing state‐of‐the‐art binders toward high‐specific‐capacity Si‐based anode applications.

Controlling Fluorescent Readout in Paper-based Analytical Devices.

Paper is an ideal candidate for the development of new disposable diagnostic devices because it is a low-cost material, allows transport of the liquid on the device by capillary action, and is environmentally friendly. Today, colorimetric analysis is most often used as a detection method for rapid tests (test strips or lateral flow devices) but usually gives only qualitative results and is limited by a relatively high detection threshold. Here, we describe studies using fluorescence as a readout tool for paper-based diagnostics. We study how the optical readout is affected by light transmission, scattering, and fluorescence as a function of paper characteristics such as thickness (grammage), water content, autofluorescence, and paper type/composition. We show that paper-based fluorescence analysis allows better optical readout compared to that of nitrocellulose, which is currently the material of choice in colorimetric assays. To reduce the loss of analyte molecules (e.g., proteins) due to adsorption to the paper surface, we coat the paper fibers with a protein-repellent hydrogel. For this purpose, we use hydrophilic copolymers consisting of N,N-dimethyl acrylamide and a benzophenone-based cross-linker, which are photochemically transformed into a fiber-attached polymer hydrogel on the paper fiber surfaces in situ. We show that the combination of fluorescence detection and the use of a protein-repellent coating enables sensitive paper-based analysis. Finally, the success of the strategy is demonstrated by using a simple LFD application as an example.

Terahertz Humidity Sensing Based on Surface-Modified Polymer Mesh Membranes with Photografting PEGMA Brush.

A simple and compact intensity-interrogated terahertz (THz) relative humidity (RH) sensing platform is successfully demonstrated in experiments on the basis of combining a porous polymer sensing membrane and a continuous THz electronic system. The RH-sensing membrane is fabricated by surface modification of a porous polymer substrate with hydrophilic and photosensitive copolymer brushes via a UV-induced graft-polymerization process. The intensity interrogation sensing scheme indicated that the power reduction of the 0.4 THz wave is dependent on the grafting density of the copolymer brushes and proportional to the RH percent levels in the humidity-controlled air-sealed chamber. This finding was verified by the water contact angle measurement. Based on the slope of the proportional relation, the best sensitivity of the hydrophilic surface-modified sensing membrane was demonstrated at 0.0423 mV/% RH at the copolymer brush density of 1.57 mg/mm3 grafted on the single side of the sensing membrane. The sensitivity corresponds to a detection limit of approximately 1% RH. The THz RH sensing membrane was proven to exhibit the advantages of low loss, low cost, flexibility, high sensitivity, high RH resolution, and a wide RH working range of 25-99%. Thus, it is a good candidate for novel applications of wearable electronics, water- or moisture-related industrial and bio-sensing.

Hydrophilic Copolymers with Hydroxamic Acid Groups as a Protective Biocompatible Coating of Maghemite Nanoparticles: Synthesis, Physico-Chemical Characterization and MRI Biodistribution Study.

Superparamagnetic iron oxide nanoparticles (SPION) with a "non-fouling" surface represent a versatile group of biocompatible nanomaterials valuable for medical diagnostics, including oncology. In our study we present a synthesis of novel maghemite (γ-Fe2O3) nanoparticles with positive and negative overall surface charge and their coating by copolymer P(HPMA-co-HAO) prepared by RAFT (reversible addition-fragmentation chain-transfer) copolymerization of N-(2-hydroxypropyl)methacrylamide (HPMA) with N-[2-(hydroxyamino)-2-oxo-ethyl]-2-methyl-prop-2-enamide (HAO). Coating was realized via hydroxamic acid groups of the HAO comonomer units with a strong affinity to maghemite. Dynamic light scattering (DLS) demonstrated high colloidal stability of the coated particles in a wide pH range, high ionic strength, and the presence of phosphate buffer (PBS) and serum albumin (BSE). Transmission electron microscopy (TEM) images show a narrow size distribution and spheroid shape. Alternative coatings were prepared by copolymerization of HPMA with methyl 2-(2-methylprop-2-enoylamino)acetate (MMA) and further post-polymerization modification with hydroxamic acid groups, carboxylic acid and primary-amino functionalities. Nevertheless, their colloidal stability was worse in comparison with P(HPMA-co-HAO). Additionally, P(HPMA-co-HAO)-coated nanoparticles were subjected to a bio-distribution study in mice. They were cleared from the blood stream by the liver relatively slowly, and their half-life in the liver depended on their charge; nevertheless, both cationic and anionic particles revealed a much shorter metabolic clearance rate than that of commercially available ferucarbotran.

Using Catechol and Zwitterion-Functionalized Copolymers to Prevent Dental Bacterial Adhesion.

In this manuscript, we report the synthesis of zwitterionic copolymers and their ability to form antifouling coatings on porous hydroxyapatite as a mimic of dental coatings. Specifically, we systematically investigated how altering the composition of copolymers of catechol methacrylate (Cat-MA or 2) and methacryloyloxyethyl phosphorylcholine (2-MPC) with varying catechol-to-zwitterion ratios impacted their adhesive and antifouling properties, allowing for the rational design of functional coatings. Characterization by ellipsometry, contact angle goniometry, and X-ray photoelectron spectroscopy revealed the presence of hydrophilic copolymer coatings of ∼10 nm thickness. Notably, these copolymers adhered to hydroxyapatite and reduced the level of attachment of both Gram-negative Escherichia coli and Gram-positive Streptococcus oralis. Additionally, in vitro experiments that mimicked the complex mouth environment (i.e., swallowing and using mouthwash) were employed to evaluate S. oralis adhesion, finding that the copolymer coatings reduced the quantity of adhered bacteria. We suggest that these copolymers provide insights into the design of antifouling coatings that are appropriate for use in oral care.

Preparation of PFPE-Based Polymeric Nanoparticles via Polymerization-Induced Self-Assembly as Contrast Agents for 19F MRI.

Fluorine-19 magnetic resonance imaging (19F MRI) probes have received considerable research interest as imaging contrast agents (CAs), but they remain neglected and underutilized due to the limited fluorine content or poor performance of fluorinated tracers. Here, we present polymeric nanoparticles (NPs) as 19F MRI CAs with a simple synthesis method and promising imaging performance. First, hydrophilic random copolymers were synthesized from oligo(ethylene glycol) methyl ether acrylate and perfluoropolyether methacrylate by reversible addition-fragmentation chain transfer (RAFT) polymerization. The optimal fluorine content, polymer concentration, and cytotoxicity as 19F MRI CAs were investigated in detail. Then, the optimal copolymer was selected as the macromolecular chain transfer agent, and the chain extension was performed with 2-(perfluorooctyl ethyl methacrylate). Subsequently, the NPs with different morphologies, such as ellipsoidal, spherical nanoparticles and vesicles, were prepared in situ by the RAFT-mediated polymerization-induced self-assembly method. In addition, the 19F MRI signal and cytotoxicity studies further confirmed that these polymeric NPs are nontoxic and have great potential as promising 19F MRI CAs for biological applications.

Investigating the electrostatic complexation of BCNO nanoparticles with a stimuli-responsive double hydrophilic graft copolymer

The co-assembly of nanoparticles within double hydrophilic block copolymers (DHBC) via electrostatic complexation is a novel approach for the development of stimuli-responsive nanodrugs with improved bioavailability, biocompatibility, intracellular uptake, and therapeutic efficacy. This study investigated the co-assembly of boron carbon oxynitride (BCNO) nanoparticles within an acid-labile polyethylene glycol-graft-polyethyleneimine (PEG-g-PEI) DHGC as a promising boron nanodrug for boron neutron capture therapy (BNCT). First, BCNO nanoassemblies are prepared by mixing the charged-neutral graft copolymer of PEG-g-PEI into a dispersion of negatively charged BCNO nanoparticles. The BCNO nanoparticles and DHGC complex were characterized using various techniques, including dynamic light scattering, zeta potential, and transmission electron microscopy (TEM). Additionally, this study investigated the change in the hydrodynamic size and zeta potential of the DHGC/BCNO nanoparticle complexation over a wide range of mixing ratios (VBCNO/VDHGC). The results revealed that the BCNO nanoassemblies formed a stable aqueous dispersion at all mixing ratios investigated in this work. In addition, the size and surface charge of the BCNO nanoassemblies can be systematically modulated by adjusting the mixing ratio, molecular weight of the charged segment, ionic strength, and pH of the solution. TEM analysis revealed that the BCNO nanoassemblies formed at a high mixing ratio exhibited polydispersed size and irregular morphologies. With decreasing mixing ratio, the size of the BCNO nanoassemblies decreased, and the cluster exhibited a spherical morphology. In addition, an increase in the molecular weight of the charged PEI segment (10,000, 60,000, and 270,000 g/mole) of the DHGC resulted in the formation of larger BCNO aggregates. Lastly, the stability and pH-responsive behavior of the BCNO nanoassemblies were investigated at pH of 6.9, 6.0, and 5.0. Under mildly acidic conditions, the Schiff base bond cleaved, which resulted in the disassembly of the BCNO aggregates into smaller clusters with a spherical morphology. The DHGC@BCNO nanoassemblies exhibited an exceptional intracellular boron uptake of 627 ng-B/104 cells in MDA-MB-231 triple-negative breast cancer cells. In comparison, cells treated with bare BCNO nanoparticles and [10B]BPA small molecular boron drug demonstrated intracellular boron uptake of only 125 ng-B/104 cells and 17 ng-B/104 cells, respectively. The study highlights the potential of electrostatic colloidal co-assembly as a synthetic tool for developing hybrid nanomaterials with remarkable intracellular boron loading. This represents a significant step towards the development of an efficacious boron drug for boron neutron capture therapy (BNCT).

Tailoring Hydrogen-Bonding Strategy for Sequence-Dependent and Thermo/pH Dual-Responsive Clusteroluminescence.

Rational design of monomer sequence for desired properties is challenging. This study investigates the effect of monomer distribution of double hydrophilic copolymers (DHCs) with electron-rich units on cluster triggered emission (CTE) capacity. By means of combining latent monomer strategy, reversible addition fragmentation chain transfer (RAFT) polymerization and selective hydrolysis technology, the random, pseudo di-block and the gradient DHCs consisting of pH-responsive polyacrylic acid (PAA) segments and thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) segments were successfully synthesized in a controlled manner. Moreover, the gradient DHCs showed a tremendously increased luminescent intensity due to the distinct hydrogen-bonding interaction compared to random and pseudo di-block DHCs. To the best of our knowledge, this is the first reported the direct correlation between luminescent intensity and sequence structure of non-conjugated polymer. Meanwhile, thermo and pH dual-responsive clusteroluminescence could be easily performed. This work demonstrates a novel and facile method to tailor the hydrogen-bonding for the stimuli-responsive light-emitting polymers.

Direct synthesis of poly(N-alkyl acrylamide) (co)polymers with pendant reactive amino groups by organocatalyzed amidation of polymethylacrylate

Post-polymerization modification of poorly reactive polyacrylates using efficient catalytic transesterification and amidation reactions has recently emerged as a valuable tool to access diversely functionalized poly(meth)acrylates and poly(meth)acrylamides. The method is particularly useful to introduce functional groups incompatible with the polymerization mechanism, such as non-protected reactive amino groups. In this work, we explored the TBD-catalyzed amidation of polymethylacrylate (PMA) with various difunctional amines to obtain polyacrylamide homo- and copolymers with a pendant reactive amine group. As anticipated, functional polymers could not be attained from amidation with ethylenediamine, because of competing cross-linking side reactions, but could be prepared from the mono-Boc-protected ethylenediamine instead, requiring, however, additional unwanted protection and deprotection steps. More interestingly, we found that the direct amidation of PMA with unprotected N-ethylethylenediamine is an efficient method for preparing secondary amine functionalized polymers, without the occurrence of crosslinking side-reaction even at lower catalyst loading. The crucial role of the ethyl group to prevent side reactions was clearly demonstrated as the use of N-methyl ethylenediamine led to crosslinking. The utility of the developed platform for the rapid preparation of a series of hydrophilic copolymers and hydrogel materials is also demonstrated. The hydrogels were prepared by reacting the secondary amine side chains with methacrylic anhydride, followed by photocuring in the presence and absence of dithiols.

Biofunctionalization of hydrogel-based scaffolds for vascular tissue regeneration

Congenital and acquired tissular losses due to disease or trauma are a major world health problem. Regenerative therapy aims to fix damaged tissues by directing the natural capacity of a host organism to use biofunctionalized artificial tissue scaffolds. These three-dimensional (3D) scaffolds can be customized with cells and/or bioactive molecules to induce cellular homing and angiogenesis, essential to ensure successful tissue regeneration. Hydrogels (HGs) scaffolds are networks of hydrophilic homopolymers, copolymers, and/or macromers with chemical and biological activities that enhance their cell colonization. The use of HGs in regenerative medicine has shown to be advantageous since HGs can be prepared under clinical-grade conditions and tailored to the specific needs of the replaced tissue. They can be made to emulate native extracellular matrices (ECMs) including physical, mechanical, and chemical cues and resilience properties. These customized HGs can reproduce the natural hygroscopic capacity of the original tissue which improves cellular anchoring, nutrition, and waste disposal. They can enable host molecular and cellular modification conducive to a natural cellular microenvironment, modifying the properties of the scaffold, and improving chemotaxis, cell adhesion, migration, proliferation, differentiation, and angiogenesis; HGs can be created and biofunctionalized with linked growth factors and synthetic peptides tailored to positively influence scaffold colonization and functional biocompatibility. This review aims to collect the most relevant information regarding biofunctionalization of HGs used for vascular tissue regeneration, their biological effects, and their clinical implications. While most biofunctionalized HGs are still under investigation, some of them have been studied in vitro, ex vivo, and in vivo with promising results. In this regard, in vivo studies have shown that biofunctionalized scaffolds with peptides such as chitosan hydrogel with LL-37 promotes angiogenesis and healing of pressure ulcers. Also, the GHK tripeptide is widely used in trials focused on guided tissue remodeling.

Self-assembly generation triggered in highly hydrophilic Pluronics® by sugars/ polyols

Micellization and micellar morphology framed by polyoxyethylene (PEO)-polyoxypropylene (PPO)-polyoxyethylene (PEO)-based very hydrophilic triblock copolymers (BCPs) viz. Pluronics® F88 and F108 in aqueous solution and in presence of sugars is investigated from cloud point (CP) and scattering (DLS and SANS) studies. As not much is explored in this direction, the current study serves a novel approach giving a detailed description on the effect of sugars: monosaccharides (mannose, glucose, galactose), disaccharides (maltose, lactose, trehalose) and polyols (mannitol, sorbitol, inositol) in varying concentration on hydrophilic BCPs. These additives promoted micellization, decreased CP with a noticeable increase in the micelle core size which is due to the dehydration of the copolymer coil. The dynamic light scattering (DLS) results inferred the slight increase in hydrodynamic micellar size in the presence of sugars/ polyols that attribute to the interaction of sugars with BCPs. According to the study, the BCP micelles in the presence of these additives had much less water in both the core and corona domains. More precisely, the dehydration occurs more in the core region than in the corona region as depicted from small-angle neutron scattering (SANS). The relative sizes of the micellar core and corona altered by different sugars/ polyols depends on the degree of dehydration which followed the hierarchy: disaccharides > polyols > monosaccharides. A precise comprehension between the molecular orbital energies for the examined systems provide the perception of sugar-stabilized Pluronics® micelles from the evaluated optimum descriptors using Gaussian 09.

Preparation and Characterization of Amorphous Solid Dispersions for the Solubilization of Fenretinide

Fenretinide (4-HPR), a retinoid derivative, has shown high antitumor activity, a low toxicological profile, and no induction of resistance. Despite these favorable features, the variability in oral absorption due to its low solubility combined with the high hepatic first pass effect strongly reduce clinical outcomes. To overcome the solubility and dissolution challenges of poorly water-soluble 4-HPR, we prepared a solid dispersion of the drug (4-HPR-P5) using a hydrophilic copolymer (P5) previously synthesized by our team as the solubilizing agent. The molecularly dispersed drug was obtained by antisolvent co-precipitation, an easy and up-scalable technique. A higher drug apparent solubility (1134-fold increase) and a markedly faster dissolution were obtained. In water, the colloidal dispersion showed a mean hydrodynamic diameter of 249 nm and positive zeta potential (+41.3 mV), confirming the suitability of the formulation for intravenous administration. The solid nanoparticles were also characterized by a high drug payload (37%), as was also evidenced by a chemometric-assisted Fourier transform infrared spectroscopy (FTIR) investigation. The 4-HPR-P5 exhibited antiproliferative activity, with IC50 values of 1.25 and 1.93 µM on IMR-32 and SH-SY5Y neuroblastoma cells, respectively. Our data confirmed that the 4-HPR-P5 formulation developed herein was able to increase drug apparent aqueous solubility and provide an extended release over time, thus suggesting that it represents an efficient approach to improve 4-HPR bioavailability.

Highly hydrophilic acrylate copolymer supported MIL-160 for air water harvesting

In this study, we prepared spherical MIL-160/PAA-NH2 composites with high atmospheric water harvesting properties by dispersing MIL-160 in a highly hydrophilic porous polyacrylate (PAA-NH2) matrix by in situ growth method. The effect of MOF loading on the crystal morphology, pore structure, and vapor adsorption/desorption properties was systematically investigated. The MOF loading of the composites can be as high as 65 wt%, along with a high water vapor adsorption capacity of 0.252 g/g at 15% of relative humidity, and can provide complete desorption under mild conditions. This work provides a new idea for efficient water harvesting at low humidity.

Mechanism Study on Mechanical Properties of Physical–Chemical Hybrid Hydrogels by Coarse-Grained Molecular Dynamics Simulations

The toughening mechanism has been a focal point for hydrogel studies. To solve the problems of the pure physical gel’s poor strength and the low toughness of pure chemical gels, hybrid physico-chemical hydrogels are devised. In this paper, we first studied the relationship between the mechanical properties and internal network structure of a physico-chemical hydrogel with hydrophilic–hydrophobic–hydrophilic triblock copolymers by coarse-grained molecular dynamics simulations. The stress and strain curves of the hydrogel system were obtained by tensile simulations, and it was found that the stress and strain curves clearly exhibit two stages with different slopes, which indicate that the aggregation of hydrophobic monomers produces a “hidden length” effect in the physico-chemical hybrid hydrogel. Then, by carrying out the cyclic tensile test and obtaining the loading–unloading curves of the hydrogel system, we found that the hydrophilic chains dominate the energy dissipation. Subsequently, the strain–stress curves at different strain rates revealed an optimal strain rate for the hydrogel’s mechanical property. Finally, we identify an optimal chain-length ratio of 7:1:7 to acquire the best mechanical properties of this hybrid hydrogel. Through this study, we have revealed that the physico-chemical hybrid hydrogel is an excellent candidate to combine the merits of a physical hydrogel and chemical hydrogel, and the length ratio between the hydrophobic and hydrophilic chains is a key for optimizing its mechanical properties.

Synthesis and characterization of UV curable biocompatible hydrophilic copolymers containing siloxane units

Tissues are highly three-dimensional structure complexes composed of different cell types and their interactions. One of the main challenges in tissue engineering is the inability to produce large, highly perfused scaffolds in which cells can grow at a high cell density and viability. Poly(dimethyl siloxane) (PDMS) is used as a flexible, biocompatible cell culture substrate with tunable mechanical properties. However, its fragility and hydrophobicity still pose a challenge. Here, we present a new strategy for the three-step one-pot synthesis of novel biocompatible hydrophilic copolymers containing siloxane units. In the first step, free radical copolymerization of acrylic acid (AA), butyl methacrylate (BMA), and 2-hydroxyethyl methacrylate (HEMA) was carried out in dioxane (DO) solution in the presence of 2,2′-azodiisobutyronitrile (AIBN). In the second step, the copolymers were modified with diepoxypropoxypropyl-terminated polydimethylsiloxane (DE-PDMS), and in the third step, the copolymers were additionally modified with glycidyl methacrylate (GMA). The modified copolymers were characterized by FTIR, NMR spectroscopy and elemental analysis. Films of modified copolymers were prepared by UV curing. SEM studies revealed microphase separated morphology with distribution of PDMS domains. The mechanical properties of the films depended on the amount of incorporated silicone modifier. The films were more hydrophilic than PDMS films. All novel copolymers showed high biocompatibility.

Surface Modification of Polyethersulfon Nanofiltration Membrane for Improving Water-Ethanol Separation

This paper reports on the surface modification of a nanofiltration polyethersulfon membrane, Microdyn Nadir NP030P, aiming at improved water-ethanol separation. To achieve this, three types of poly(vinyl alcohol) copolymers of varied hydrophilic-lipophilic balance were synthesized and tested as modifiers: double hydrophilic graft copolymer with poly(N,N-dimethyl acrylamide) side chains, amphiphilic copolymer of partially acetalized PVA, as well as amphiphilic copolymer with grafted hydrophobic poly(methyl methacrylate) chains. Copolymers’ chemical structure, composition and properties were evaluated by conventional analytical techniques. Thin film deposition via spin-coating of copolymer solution was applied as a method for membrane modification. Alteration of the hydrophilic-lipophilic balance at the membrane surface was studied by contact angle measurements whereas the surface microstructure was characterized by attenuated total reflectance Fourier-transform infrared spectroscopy as well as optical and scanning electron microscopy. The feasibility of tailoring membrane surface to specific requirements by using PVA-based copolymer was assessed and the influence of copolymer structure and composition on the membrane properties was considered.

Multiblock poly(ether-b-amide) copolymers comprised of PA1212 and PPO-PEO-PPO with specific moisture-responsive and antistatic properties

Functional multiblock poly(ether-b-amide) (PEBA) copolymers, comprised of PA1212 (polyamide 1212) as hard segments and Jeffamine ED-2003 as soft segments, were successfully prepared via two-step melt polycondensation without any amidation catalyst. Here, using diamino-terminated poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) (PPO-PEO-PPO), Jeffamine ED-2003, enhances the compatibility between polyamide oligomer and polyether, which is better than the traditional route using hydroxyl-terminated polyether. The chemical structure of multiblock PEBAs, as well as the microphase separated structure with crystalline phase of polyamide and polyether, were confirmed by heteronuclear multiple-bond correlation spectrum, heteronuclear multiple quantum correlation spectrum, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry and dynamic mechanical analysis. The hydrophilic PEBA copolymers showed water adsorption ranging from 87.3% to 17.1% depending on the polyether content, and specially showed moisture responsive behavior within seconds when exposed to moisture. The corresponding mechanism was studied using time-resolved attenuated total reflectance FT-IR spectroscopy in the molecular level and the water diffusion coefficient was estimated to be 1.07 × 10–8 cm2∙s–1. Two-dimensional correlation FT-IR spectra analysis was performed to confirm that the interaction between water and polyether phase was in preference to that between water and polyamide matrix, and water molecule only forms hydrogen bond with the polyether segment. Due to the incorporation of PEO segments, the PEBAs have the surface resistivity varying from 5.6 × 109 to 6.5× 1010 Ω, which makes PEBA potential candidate as permanent antistatic agent.

Water-soluble polyphosphonate-based bottlebrush copolymers via aqueous ring-opening metathesis polymerization.

Ring-opening metathesis polymerization (ROMP) is a versatile method for synthesizing complex macromolecules from various functional monomers. In this work, we report the synthesis of water-soluble and degradable bottlebrush polymers, based on polyphosphoesters (PPEs) via ROMP. First, PPE-macromonomers were synthesized via organocatalytic anionic ring-opening polymerization of 2-ethyl-2-oxo-1,3,2-dioxaphospholane using N-(hydroxyethyl)-cis-5-norbornene-exo-2,3-dicarboximide as the initiator and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the catalyst. The resulting norbornene-based macromonomers had degrees of polymerization (DPn) ranging from 25 to 243 and narrow molar mass dispersity (Đ ≤ 1.10). Subsequently, these macromonomers were used in ROMP with the Grubbs 3rd-generation bispyridyl complex (Ru-G3) to produce a library of well-defined bottlebrush polymers. The ROMP was carried out either in dioxane or in aqueous conditions, resulting in well-defined and water-soluble bottlebrush PPEs. Furthermore, a two-step protocol was employed to synthesize double hydrophilic diblock bottlebrush copolymers via ROMP in water at neutral pH-values. This general protocol enabled the direct combination of PPEs with ROMP to synthesize well-defined bottlebrush polymers and block copolymers in water. Degradation of the PPE side chains was proven resulting in low molar mass degradation products only. The biocompatible and biodegradable nature of PPEs makes this pathway promising for designing novel biomedical drug carriers or viscosity modifiers, as well as many other potential applications.