Glycol Methyl Ether Methacrylate Research Articles

Reversible Stimuli-Dependent Aggregation-Induced Emission from a "Nonfluorescent" Amphiphilic PVDF Graft Copolymer.

A poly(vinylidine fluoride) graft random copolymer of t-butyl aminoethyl methacrylate (tBAEMA) and oligo(ethylene glycol) methyl ether methacrylate (OEGMA, Mn = 300) [PVDF-g-P(tBAEMA-ran-OEGMA), PVBO] is synthesized by atom transfer radical polymerization (ATRP), and PVBO is fractionated to get a highly water-soluble fraction (PVBO-1) showing a reversible on/off fluorescence behavior with gradual increase and decrease in pH, respectively, achieving a maximum quantum yield of 0.18 at pH = 12. PVBO-1 dissolved in water shows large multimicellar aggregates (MMcA), but at pH 12, crumbling of larger aggregates to much smaller micelles occurs, forming nonconjugated polymer dots (NCPDs), as supported by transmission electron microscopy and dynamic light scattering study. The reversible fluorescence on/off behavior also occurs with the decrease and increase of temperature. Theoretical study indicates that, at high pH, most of the amino groups become neutral and exhibit a strong tendency to form aggregates from crowding of a large number of carbonyl and amine groups, minimizing the HOMO-LUMO gap, showing an absorption peak at the visible region, and generating aggregation-induced emission.

Nanogels with High Loading of Anesthetic Nanocrystals for Extended Duration of Sciatic Nerve Block.

The development of thermoresponsive nanogels loaded with nanocrystals of the local anesthetic bupivacaine nanocrystals (BNCs) for prolonged peripheral nerve pain relief is reported here. BNCs were prepared using the antisolvent precipitation method from the hydrophobic form of bupivacaine (bupivacaine free base). The as-prepared BNCs were used stand-alone or encapsulated in temperature-responsive poly(ethylene glycol) methyl ether methacrylate (OEGMA)-based nanogels, resulting in bupivacaine NC-loaded nanogels (BNC-nanogels) of monodisperse size. The synthesis protocol has rendered high drug loadings (i.e., 93.8 ± 1.5 and 84.8 ± 1.2 wt % for the NC and BNC-nanogels, respectively) and fast drug dissolution kinetics in the resulting composite material. In vivo tests demonstrated the efficacy of the formulation along with an extended duration of sciatic nerve block in murine models of more than 8 h with a formulation containing only 2 mg of the local anesthetic thanks to the thermoresponsive character of the polymer, which, at body temperature, becomes hydrophobic and acts as a diffusion barrier for the encapsulated drug nanocrystals. The hydrophobicity of the encapsulated bupivacaine free base probably facilitates its pass through cell membranes and also binds strongly to their hydrophobic lipid bilayer, thereby protecting molecules from diffusion to extracellular media and to the bloodstream, reducing their clearance. When using BNC-nanogels, the duration of the anesthetic blockage lasted twice as long as compared to the effect of just BNCs or a conventional bupivacaine hydrochloride solution both containing equivalent amounts of the free drug. Results of the in vivo tests showed enough sensory nerve block to potentially relieve pain, but still having mobility in the limb, which enables motor function when required. The BNC-nanogels presented minimal toxicity in the in vivo study due to their sustained drug release and excellent biocompatibility. The encapsulation of nano-sized crystals of bupivacaine provides a prolonged regional anesthesia with reduced toxicity, which could be advantageous in the management of chronic pain.

Silica Nanoparticle Reinforced Composites as Transparent Elastomeric Damping Materials

Inspired by the structure of the cornea, which is the transparent front part of the eye, we developed a transparent and tough silica composite elastomer consisting of poly[di(ethylene glycol)methyl ether methacrylate] (PMEO2MA) and 110 nm spherical silica particles without using an organic cross-linking agent. While filler composite elastomers, such as reinforced rubbers, have complex compositions containing multiple additives (dispersants, plasticizers, vulcanizing agents, etc.), the composition of our composite elastomer is very simple. With an increased amount of silica particles, the fracture energy of the composite elastomer (20.2 MJ m–3) was improved by 25 times compared to that of unfilled PMEO2MA (0.8 MJ m–3). Nanoscale mapping using atomic force microscopy elucidated the presence of an interface layer (IL) of approximately 15 nm thickness with a high elastic modulus near the silica particles in the composite elastomer. The fracture energy of the composite elastomer was found to be a maximum when the particle surface distance was approximately 30 nm. This particle surface distance meant that the ILs were just in contact with each other. The surface charge density and Hansen solubility parameter of the silica particles indicated the ionization of silanol groups and interactions caused by hydrogen bonding between polymer chains and the silica surface. The array of silica particles embedded with intervals of a few nanometers was expected to be able to effectively dissipate deformation energy as heat due to shear strain and friction between the particle surface and polymer matrices. Measurements of the vibration-damping properties revealed that the loss factor of the composite elastomer was significantly higher than that of the unfilled elastomer, indicating that the composite elastomer in this study could be applied as an interlayer film for laminated glass in automotive and architectural applications.

Optimizing the Polymer Cloak for Upconverting Nanoparticles: An Evaluation of Bioactivity and Optical Performance.

The ability of upconversion nanoparticles (UCNPs) to convert low-energy near-infrared (NIR) light into high-energy visible-ultraviolet light has resulted in their development as novel contrast agents for biomedical imaging. However, UCNPs often succumb to poor colloidal stability in aqueous media, which can be conquered by decorating the nanoparticle surface with polymers. The polymer cloak, therefore, plays an instrumental role in ensuring good stability in biological media. This study aims to understand the relationship between the length and grafting density of the polymer shell on the physicochemical and biological properties of these core-shell UCNPs. Poly(ethylene glycol) methyl ether methacrylate block ethylene glycol methacrylate phosphate (PPEGMEMAn-b-PEGMP3) with different numbers of PEGMEMA repeating units (26, 38, and 80) was prepared and attached to the UCNPs via the phosphate ligand of the poly(ethylene glycol methacrylate phosphate) (PEGMP) block at different polymer densities. The in vitro and in vivo protein corona, cellular uptake in two-dimensional (2D) monolayer and three-dimensional (3D) multicellular tumor spheroid (MCTS) models, and in vivo biodistribution in mice were evaluated. Furthermore, the photoluminescence of single-polymer-coated UCNPs was compared in solid state and cancer cells using laser scanning confocal microscopy (LSCM). Our results showed that the bioactivity and luminescence properties are chain length and grafting density dependent. The UCNPs coated with the longest PPEGMEMA chain, grafted at low brush density, were able to reduce the formation of the protein corona in vitro and in vivo, while these UCNPs also showed the brightest upconversion luminescence in the solid state. Moreover, these particular polymer-coated UCNPs showed enhanced cellular uptake, extended in vivo blood circulation time, and more accumulation in the liver, brain, and heart.

Influence of the Polymer Microstructure over the Phase Separation of Thermo-Responsive Nanoparticles.

Thermo-responsive nanoparticles (NPs), i.e., colloids with a sharp and often reversible phase separation in response to thermal stimuli, are coming to the forefront due to their dynamic behavior, useful in applications ranging from biomedicine to advanced separations and smart optics. What is guiding the macroscopic behavior of these systems above their critical temperature is mainly the microstructure of the polymer chains of which these NPs are comprised. Therefore, a comprehensive understanding of the influence of the polymer properties over the thermal response is highly required to reproducibly target a specific behavior. In this study, we synthesized thermo-responsive NPs with different size, polymeric microstructure and hydrophilic-lipophilic balance (HLB) and investigated the role of these properties over their phase separation. We first synthesized four different thermo-responsive oligomers via Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization of poly(ethylene glycol)methyl ether methacrylate. Then, exploiting the RAFT living character, we chain-extended these oligomers with butyl methacrylate obtaining a library of NPs. Finally, we investigated the NP thermo-responsive behavior, their physical state above the cloud point (Tcp) as well as their reversibility once the stimulus is removed. We concluded that the solid content plays a minor role compared to the relative length of the two blocks forming the polymer chains. In particular, the longer the stabilizer, the more favored the formation of a gel. At the same time, the reversibility is mainly achieved at high HLB, independently from the absolute lengths of the block copolymers.

ABC Triblock Copolymers Antibacterial Materials Consisting of Fluoropolymer and Polyethylene Glycol Antifouling Block and Quaternary Ammonium Salt Sterilization Block.

Due to their various applications in human healthcare and industrial fields, engineering surfaces with antiadhesion and antibacteria properties is still a challenging task. In this work, the fluoropolymer with low surface energy and poly(poly(ethylene glycol) methyl ether methacrylate) (PEGMA) with electrostatic repulsion and interfacial hydration was chosen as a common antiadhesion block and quaternary ammonium salt with bactericide properties as a sterilization block. The triblock copolymers of poly(2-(dimethylamino)ethyl methacrylate)-b-poly(poly(oligo ethylene glycol) methyl ether methacrylate)-b-poly(dodecafluoroheptyl methacrylate) (PDMAEMA-b-PEGMA-b-PDFHMA) were synthesized by the reversible addition-fragmentation chain transfer (RAFT) polymerization method. Then, the synthesized triblock copolymers were quaternized to obtain the antibacterial materials (QPDMAEMA-b-PEGMA-b-PDFHMA). It has been found that the QPDMAEMA-b-PEGMA-b-PDFHMA triblock copolymer coating has excellent antiadhesion and antibacterial properties against S. aureus and E. coli. The synergistic effects of fluoropolymer and PEGMA can enhance the antifouling properties of the coating. At the same time, it has a good antifouling effect on platelets and red blood cells. In addition, the triblock copolymer coating has long-term stability in high ionic strength solution of PBS in dynamic conditions. These kind of materials with antifouling and antibacterial properties may have potential applications on the surface of various public utilities and medical equipment.

Stimuli-Responsive Proteinosomes Based on Biohybrid Shell Cross-Linked Micelles

A new method of stimuli-responsive proteinosome fabrication with the shell cross-linked micelle as a template is reported in this research. A thermoresponsive diblock copolymer poly[di(ethylene glycol) methyl ether methacrylate]-b-poly[poly(ethylene glycol) methyl ether methacrylate-co-pyridyl disulfide methacrylamide] [PDEGMA-b-P(PEGMA-co-PDSMA)] was synthesized and self-assembled into micelles with PDEGMA cores and P(PEGMA-co-PDSMA) shells at the temperature above its lower critical solution temperature (LCST). Reduced bovine serum albumin (BSA) molecules with six thiol groups were used to cross-link the shells of the micelles by reacting with the pendant pyridyl disulfide groups on the P(PEGMA-co-PDSMA) block. At a temperature below the LCST of the polymer, the PDEGMA cores were dissolved in water, affording proteinosomes with a size of about 50 nm and capsule-like structures. The proteinosome was also thermoresponsive with a phase transition temperature at 35 °C. The fabrication of the proteinosome had no obvious influence on the structure and activity of BSA, and BSA retained most of its secondary structure and esterase-like activity. Because the BSA molecules were connected to the polymer chains through disulfide bonds, they could be released upon addition of dithiothreitol. The in vitro cell viability evaluation and the cellular uptake assay demonstrated that the proteinosome showed low toxicity to NIH 3T3 and 4T1 cells and could be internalized into the 4T1 cells.

Hydration in thermo-responsive oligoether methacrylate hydrogels studied by FT-IR spectroscopy

Hydration in thermo-responsive polymer hydrogels, such us poly(oligo(ethylene glycol) methyl ether methacrylates) (POEGMAs) is a key factor in understanding their thermo-responsivity. The hydration of POEGMAs with different length of side groups was comprehensively studied for the first time. The comparative studies have shown that hydration of different hydrophilic centres in various POEGMAs is similar and independent of oligoether chain length. Only some quantitative differences in bound water structure, especially at the first stage of hydration have been found. However, the crystallinity (if it occurs) significantly impacts on the hydration process. Finally, the water structure is the closer to the bulk water structure in the fully swollen PMEO2MA hydrogel than in other POEGMA systems with longer oligoether side groups.

Recyclable DMAP-Functionalized polymeric nanoreactors for highly efficient acylation of alcohols in aqueous systems

Fabrication of highly efficient and recyclable nanoreactors via macromolecular self-assembly represents a promising strategy for green organic transformation. In this study, small-molecule catalysts 4-(N,N-dimethylamino)pyridine (DMAP) functionalized nanoreactors were constructed by self-assembly of amphiphilic block copolymers with DMAP moieties in the hydrophobic block, leading to heterogeneous catalysts with excellent dispersity in water. The key preparation route included reversible addition-fragmentation chain transfer (RAFT) polymerization of 2-(N-methyl-N-(4-pyridyl)amino)ethyl methacrylate (MAPMA) and methyl methacrylate (MMA) using poly (oligomeric (ethylene glycol) methyl ether methacrylate) (POEGMA) as a hydrophilic macromoleculer RAFT reagent. The characterization by dynamic light scattering (DLS) and transmission electron microscopy (TEM) shows that the nanoreactors possess a core-shell nanostructure with the diameter of around 110 nm. The resulting polymeric nanoreactors showed excellent catalytic activity for acylation of alcohols in water. High conversion of a variety of alcohol (>99%) and excellent product selectivity were achieved. The high catalytic efficiency of the nanoreactors may be attributed to the enhancement of the interaction between the reactant and the catalyst in the confined hydrophobic space, which simulates how enzymes usually work. Moreover, the catalyst could be easily recovered by thermos-responsive separation and reused with high activity for more than 5 cycles. This study presents an efficient approach to achieve green catalytic reactions which are normally incompatible to aqueous conditions, potentially applicable to other catalytic systems such as metal-mediated organic transformations.

An intracellular enzyme-responsive polymeric prodrug with synergistic effect of chemotherapy and two-photon photodynamic therapy

The combination of chemotherapy/photodynamic therapy (PDT) has shown synergistically enhanced anticancer efficacies. However, precise delivery of therapeutic agents to the site-of-action and activation of PDT in deep tissues are still challenging. Herein, a poly [oligo (ethylene glycol) methyl ether methacrylate] (polyOEGMA)-functionalized dendritic polymer-paclitaxel prodrug with a hydrophobic core was designed and prepared to encapsulate pyropheophorbide a (PPa) and an imidazole derivative, two-photon (TP) absorption compound T1. As a short peptide GFLG that was sensitive to intracellular cathepsin B was inserted into the branches of the dendritic polymer and also used as a linker to conjugate paclitaxel (PTX) to the polymer, the nanosystem released PTX in a tumor microenvironment-responsive manner and was partially degraded. The TP compound T1 had a high energy-transfer efficiency and displayed an enhanced two-photon photodynamic therapy (TP-PDT) effect, thus resulting in an increased anticancer efficacy, which was confirmed with the results of in situ TP-PDT anti-tumor efficiencies and apoptosis assays. The synergistic effect on inhibition of tumor growth in the 4T1 xenograft mice was achieved due to the combination of chemotherapy (PTX) and PDT (PPa or TP-PDT compound T1). Importantly, the chemo/TP-PDT combined system achieved a much higher tumor growth inhibition (TGI, 67.23%) in the tissue surrounded with thick swine muscle as compared to the group treated with PTX and PPa (48.92%). The prodrug-based nanosystem loaded with PTX and TP-PDT agents could overcome the challenge of conventional one-photon PDT with a short penetration depth into tissues to achieve a notably enhanced synergistic anticancer efficacy.

Fabrication and Impact of Fouling-Reducing Temperature-Responsive POEGMA Coatings with Embedded CaCO3 Nanoparticles on Different Cell Lines.

In the present work, we have successfully prepared and characterized novel nanocomposite material exhibiting temperature-dependent surface wettability changes, based on grafted brush coatings of non-fouling poly(di(ethylene glycol)methyl ether methacrylate) (POEGMA) with the embedded CaCO3 nanoparticles. Grafted polymer brushes attached to the glass surface were prepared in a three-step process using atom transfer radical polymerization (ATRP). Subsequently, uniform CaCO3 nanoparticles (NPs) embedded in POEGMA-grafted brush coatings were synthesized using biomineralized precipitation from solutions of CaCl2 and Na2CO3. An impact of the low concentration of the embedded CaCO3 NPs on cell adhesion and growth depends strongly on the type of studied cell line: keratinocytes (HaCaT), melanoma (WM35) and osteoblastic (MC3T3-e1). Based on the temperature-responsive properties of grafted brush coatings and CaCO3 NPs acting as biologically active substrate, we hope that our research will lead to a new platform for tissue engineering with modified growth of the cells due to the release of biologically active substances from CaCO3 NPs and the ability to detach the cells in a controlled manner using temperature-induced changes of the brush.

Polymeric micelles with anti-virulence activity against Candida albicans in a single- and dual-species biofilm

Infections caused by fungal biofilms with rapidly evolving resistance against the available antifungal agents are difficult to manage. These difficulties demand new strategies for effective eradication of biofilms from both biological and inert surfaces. In this study, polymeric micelles comprised of di-block polymer, poly-(ethylene glycol) methyl ether methacrylate and poly 2-(N,N-diethylamino) ethyl methacrylate polymer, P(PEGMA-b-DEAEMA), were observed to exhibit remarkable inhibitory effects on hyphal growth of Candida albicans (C. albicans) and C. tropicalis, thus preventing biofilm formation and removing existing biofilms. P(PEGMA-b-DEAEMA) micelles showed biofilm removal efficacy of > 40% and a 1.4-log reduction in cell viability of C. albicans in its single-species biofilms. In addition, micelles alone promoted high removal percentage in a mixed biofilm of C. albicans and C. tropicalis (~ 70%) and remarkably reduced cell viability of both strains. Co-delivery of fluconazole (Flu) and amphotericin B (AmB) with micelles showed synergistic effects on C. albicans biofilms (3-log reduction for AmB and 2.2-log reduction for Flu). Similar effects were noted on C. albicans planktonic cells when treated with the micellar system combined with AmB but not with Flu. Moreover, micelle-drug combinations showed an enhancement in the antibiofilm activity of Flu and AmB against dual-species biofilms. Furthermore, in vivo studies using Caenorhabditis elegans nematodes revealed no obvious toxicity of the micelles. Targeting morphologic transitions provides a new strategy for defeating fungal biofilms of polymorphic resistance strains and can be potentially used in counteracting Candida virulence.

Random copolymer of poly(polyethylene glycol methyl ether)methacrylate as tunable transition temperature solid-solid phase change material for thermal energy storage

Polymer based phase change materials (PCM) for thermal energy storage (TES) applications have gained some attention recently due to their high stability and potential solid to solid phase transition. Here, we are the first to utilize a simple copolymerization strategy for static tunability transition temperature (Tt) of polymeric PCM. The copolymerization between short and long side chain polyethylene glycol based methacrylate polymers was designed to tune Tt with minimum impact on their energy density. Polarized optical microscope and x-ray techniques were also used to understand the relationship between crystal structure and Tt of different copolymer composition which was discussed in the context. The solid to solid transition polymeric PCM were successfully developed with tunable Tt ranged from 18 °C to 35 °C which is suitable toward building envelop applications.

Poly(oligo(ethylene glycol) methyl ether methacrylate) Capped pH-Responsive Poly(2-(diethylamino)ethyl methacrylate) Brushes Grafted on Mesoporous Silica Nanoparticles as Nanocarrier.

In this paper, a new pH-responsive nanosystem based on mesoporous silica nanoparticles (MSNs) was developed for cancer therapy. Poly(2-(diethylamino) ethyl methacrylate) (PDEAEMA) was grafted on their outer surface and acts as a gatekeeper, followed by subsequent modification of the polymer by cysteine (MSN-PDEAEMA-Cys) and poly(oligo(ethylene glycol) methyl ether methacrylate) (MSN-PDEAEMA-Cys-POEGMEMA). The physicochemical properties of these nanocarriers were characterized using scanning and transmission electron microscopies (SEM and TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and dynamic light scattering (DLS). The synthesized nanoparticles were well-dispersed with a diameter of ca. 200 nm. The obtained XPS results confirm the successful modification of MSN-PDEAEMA with Cys and POEGMEMA by increasing the peak intensity of C–O and C=O groups at 286.5 and 288.5 eV, respectively. An anti-cancer drug, doxorubicin (DOX), was encapsulated into the fabricated nanoplatform. The DOX release amount at physiological pH of 7.4 was limited (10%), while an accumulation drug release of ca. 35% was accomplished after 30 h in acidic media. The MTT cell line was used to assess the cytotoxicity of the unloaded and DOX-loaded fabricated nanoplatforms. Upon loading of DOX on these nanomaterials, they showed significant toxicity to human liver cancer cells. These results suggest that the prepared nano-structured materials showed good biocompatibility as well, and they can serve as nanocarriers for the delivery of anti-cancer drugs.

Eco-friendly colorization of textile originating from polydopamine nanofilm structural color with high colorfastness

Traditional textile dyeing industry usually use chemical pigments and dyes, which bring about a large amount of colored wastewater causing serious environmental pollution. Replacing the traditional high pollution dyeing methods to realize eco-friendly dyeing is very important to the textile dyeing industry, structural colorization maybe one of the most promising methods. In this study, a novel approach was proposed to fabricate eco-friendly coloration of textile originating from polydopamine (PDA) structural color nanofilm with high colorfastness. Four different bright colors were obtained by the polymerization of PDA nanofilm with different reaction times on cotton fabric. However, capillary tension during the formation of PDA nanofilm and weak interaction with fabric substrate resulted in cracking and poor colorfastness. The novel synthesis adhesive of poly (glycidyl methacrylate co-polyethylene glycol methyl ether methacrylate) containing reactive epoxy groups was used to avoid cracking and improve the colorfastness which would form covalent bond on the interface between structural color film and substrate. Therefore, crack-free PDA structural color nanofilm with high colorfastness on cotton fabric surface was obtained. This facile approach provide novel idea for eco-friendly dyeing different kinds of textiles with structural color boosting the cleaner dyeing in textile industrial field.

Cylindrical polymer brushes-anisotropic unimolecular micelle drug delivery system for enhancing the effectiveness of chemotherapy

Polymer systems can be designed into different structures and morphologies according to their physical and chemical performance requirements, and are considered as one of the most promising controlled delivery systems that can effectively improve the cancer therapeutic index. However, the majority of the polymer delivery systems are designed to be simple spherical nanostructures. To explore morphology/size-oriented delivery performance optimization, here, we synthesized three novel cylindrical polymer brushes (CPBs) by atom transfer radical polymerization (ATRP), which were cellulose-g-(CPT-b-OEGMA) (CCO) with different lengths (~86, ~40, and ~21 nm). The CPBs are composed of bio-degradable cellulose as the carrier, poly(ethylene glycol) methyl ether methacrylate (OEGMA) as hydrophily block, and glutathione (GSH)-responsive hydrophobic camptothecin (CPT) monomer as loaded anticancer drug. By controlling the chain length of the initiator, three kinds of polymeric prodrugs with different lengths (CCO-1, CCO-2, and CCO-3) could be self-organized into unimolecular micelles in water. We carried out comparative studies of three polymers, whose results verified that the shorter CPBs exhibited higher drug release efficiency, more cellular uptake, and enhanced tumor permeability, accompanied by shortened blood circulation time and lower tumor accumulation. As evidenced by in vivo experiments, the shorter CPBs exhibited higher anti-tumor efficiency, revealing that the size advantage has a higher priority than the anisotropic structure advantage. This provided vital information as to design an anisotropic polymer-based drug delivery system for cancer therapy.

Lignin-based thermoresponsive macromolecules via vitamin-induced metal-free ATRP

An environmentally-friendly process for the modification of lignin with thermoresponsive polymers was employed, providing well-defined structures with narrow molecular weight distribution (Mw/Mn = 1.44). We report a biocompatible vitamin-inspired photoinitiation system composed of two components i.e. riboflavin (vitamin B2) as a photosensitizer and ascorbic acid (vitamin C) as a mild reducing agent. Under blue light LEDs irradiation at 460 nm (5.0 mW cm−2) the presented two-component photoinitiation setup enables grafting of poly(ethylene glycol) methyl ether methacrylate (OEGMA500) from brominated lignin via metal-free ATRP approach. A series of cyclic voltammetry (CV) measurements were conducted to electrochemically characterize ATRP initiators, both brominated lignin and lignin-based polymers, confirming preserved chain-end functionality of the prepared macromolecules. Received polymers with lignin core and POEGMA side chains exhibited thermoresponsive properties, which were investigated by determination of number average sizes of macromolecules by dynamic light scattering (DLS) and transmittance by ultraviolet/visible (UV-Vis) absorption spectroscopy of KL-g-(POEGMA-Br)10 aqueous solution. The in vitro curcumin release studies showed that the active substance is released from drug-loaded micelles in a thermo-sensitive manner. Prepared lignin-based macromolecules will show wide application as crucial components of thermoresponsive coatings, potentially creating bioactive surfaces characterized by antifouling properties, controlling cell adhesion or used as biosensors, due to PEG-containing side chains in branched polymers.

Synthesis of bio‐based poly(methacrylates) using SG1‐containing amphiphilic macroinitiators by nitroxide mediated miniemulsion polymerization

AbstractSG1‐based amphiphilic macroinitiators were synthesized from oligoethylene glycol methyl ether methacrylate and 10 mol% acrylonitrile or styrene (as the controlling comonomer) to conduct the nitroxide mediated polymerization of bio‐based methacrylic monomers (isobornyl methacrylate (IBOMA) and C13 alkyl methacrylate (C13MA)) in miniemulsion. The effect of the addition of surfactant (DOWFAX 8390), co‐stabilizer (n‐hexadecane) and different reaction temperatures (80, 90 and 100°C) on polymerization kinetics was studied. We found that the NMP of IBOMA/C13MA using amphiphilic macroalkoxyamines were most effective during miniemulsion polymerization (linear trend of Mn versus conversion and high latex stability) in presence of 2 wt% surfactant and 0.8 wt% co‐stabilizer (relative to monomer) at 90°C. The effect of surfactant, co‐stabilizer and temperature on particle size during the polymerization was studied and suggested a decrease in initial particle size with the addition of surfactant and co‐stabilizer. Finally, the thermal properties of IBOMA/C13MA polymers, prepared by amphiphilic macroinitiators, were examined thoroughly, indicating a Tg in the range of −44°C < Tg < 109°C.

Encapsulation of CuO nanoparticles inside the channels of the multi-walled carbon nanotubes functionalized with thermal stress

Commercially available multi-walled carbon nanotubes (MWCNTs), which are generally naturally intertwined, were cut by sudden, repeated exposure to oxidizing conditions in the air. This process has been proved to be an effective handle of producing open ended and medium level functionalization. Results showed that the typical closed graphite end caps for carbon nanotubes via functionalized with thermal stress (CNT-M) can be shorten long MWCNTs, while improving average graphite quality. These results were supported by the increase of Brunauer–Emmett–Teller (BET) surface area from 284.772 m2g−1 to 463.890 m2g−1. Copper oxide nanoparticles (CuO-PEGx) which were synthesized using polyethylene glycol (PEG) nonionic surfactants with different derivative (polyethylene glycol methyl ether methacrylate) and molecular weights (Mw: 200, 2000 and 5000), were encapsulated into CNT-Ms by simple wet impregnation technique. The filling capacity depended on the preparation conditions and particle size of CuO nanostructures. While other samples showed a multiple particle size distribution, only CNT-M-CuO-PEG950 sample indicated uniform particle size distribution with the smallest particles (3.6 nm) inside CNT-M channels. The BET surface areas of the nanocomposites (274.865–304.859 m2g−1) were lower than the surface area (463.890 m2g−1) of CNT-Ms while they were close and large to the surface area of MWCNTs (284.772 m2g−1).

Multifaceted pH and Temperature Induced Self‐Assembly of P(DMAEMA‐co‐LMA)‐b‐POEGMA Terpolymers and Their Cationic Analogues in Aqueous Media

AbstractThis work focuses on the synthesis of novel amphiphilic block terpolymers of the type poly[(2‐(N,N‐dimethylamino) ethyl methacrylate)‐co‐(lauryl methacrylate)]‐b‐poly[(oligo ethylene glycol) methyl ether methacrylate] (P(DMAEMA‐co‐LMA)‐b‐POEGMA)) by reversible addition‐fragmentation chain transfer polymerization. The cationic amphiphilic polyelectrolyte analogs P(QDMAEMA‐co‐LMA)‐b‐POEGMA are obtained through quantitative quaternization of the DMAEMA segments. Molecular characterization by size exclusion chromatography, nuclear magnetic resonance, and Fourier Transform Infrared spectroscopies indicates the successful synthesis of these novel series of block terpolymers. The amine forms of the block copolymers respond to pH and temperature changes in aqueous solutions by forming unimolecular or multichain nanoaggregates of varying size, micropolarity, and internal structure, as indicated by light scattering and fluorescence spectroscopy techniques. At neutral and basic pH, the existence of micellar like nanoassemblies is observed in the solutions of P(DMAEMA‐co‐LMA)‐b‐POEGMA terpolymers, while aggregation into micellar‐like clusters take place at temperature values above room temperature due to the presence of the hydrophobic LMA segments. Unexpectedly, the cationic polyelectrolytes P(QDMAEMA‐co‐LMA)‐b‐POEGMA counterparts show temperature responsiveness as a consequence of the amphiphilicity of the polymeric system.