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[Display omitted] • A hydroxyl-functionalized isotactic polypropylene was synthesized via solution polymerization and grafted onto alternating styrene- co -maleic anhydride copolymer through transesterification reaction. • The amphiphilic graft-copolymers with varying comonomers content were obtained either via solution process or reactive extrusion. • All the graft-copolymers and their precursors were analyzed in terms of molecular structure as well as thermal properties. The copolymers were used as bitumen modifier to verify their suitability for road constructions. • The bulk and rheological properties of the polymer modified bitumen samples were evaluated together with their morphology and nanomechanical properties. High-temperature Performance Grade limits of the samples were determined. Here we demonstrate the application of hydroxyl-functionalized propylene-based copolymers, poly(propylene- co -1-hexene- co -10-undecen-1-ol) (FPP) and poly(styrene- co -maleic anhydride) (SMA) graft copolymers derived thereof, poly(propylene- co -1-hexene- graft -styrene- co -maleic anhydride) (FPP- g -SMA) as bitumen modifiers. The FPP samples were synthesized via solution copolymerization, while FPP- g -SMA products were obtained via transesterification of FPP with SMA either in solution or by a melt-grafting process. FPP -g- SMA modifiers prepared in solution, having a SMA content of around 30 wt%, performed very well as compatibilizer for bitumen, generating a polymer-modified compositions with a uniform morphology and improved nanomechanical properties, storage stability, rheological properties and high-temperature performance as compared to neat bitumen samples. [ABSTRACT FROM AUTHOR]

Curcumin (Cur), an antioxidant molecule, has multiple medicinal properties and displays therapeutic values. However, in some functional food applications, the incorporation of Cur is limited because of its poor solubility and inherent physicochemical instability. Herein, to address these issues, PEGylated poly (trimethylene carbonate) (MPEG-PTMC) was used as the polymeric carrier for fabricating the Cur loaded nanoparticles (MPEG-PTMC@Cur NPs). The MPEG-PTMC@Cur NPs had an average size of ∼130 nm. Importantly, after being incorporated in MPEG-PTMC@Cur NPs, the photochemical stability of Cur was significantly enhanced. The degradation rate of Cur was only about 15%. Furthermore, the MPEG-PTMC@Cur NPs exhibited improved DPPH scavenging ability (SC 25 = 14.40 μg/mL) compared with that of the free Cur (SC 25 > 30 μg/mL). Importantly, the pharmacokinetic study demonstrated that the oral relative bioavailability of MPEG-PTMC@Cur NPs was significantly improved. All these results support that MPEG-PTMC@Cur NPs could be an effective delivery system for Cur. [Display omitted] • MPEG-PTMC was used as the polymeric carrier for fabricating the Cur loaded nanoparticles. • After being incorporated in MPEG-PTMC@Cur NPs, the photochemical stability of Cur was significantly enhanced. • The MPEG-PTMC@Cur NPs possessed superior antioxidant activities compared with that of free Cur. [ABSTRACT FROM AUTHOR]

New cis -bis[ N -(2-nitroxyethyl)isonicotinamide- N ]platinum(iv) tetrachloride hybrid materials were obtained via its solubilization by nanoparticles of N -vinylpyrrolidone copolymer with dimethacrylates and characterized. The materials containing 2% of PtIV complex cause a cytotoxic effect on the tumor A-172 cells; IC50 values were ca. 106 μm after incubation for 48 h. [ABSTRACT FROM AUTHOR]

Reactions inside confined compartments at the nanoscale represent an essential step in the development of complex multifunctional systems to serve as molecular factories. In this respect, the biomimetic approach of combining biomolecules (proteins, enzymes, mimics) with synthetic membranes is an elegant way to create functional nanoreactors, or even simple artificial organelles, that function inside cells after uptake. Functionality is provided by the specificity of the biomolecule(s), whilst the synthetic compartment provides mechanical stability and robustness. The availability of a large variety of biomolecules and synthetic membranes allows the properties and functionality of these reaction spaces to be tailored and adjusted for building complex self-organized systems as the basis for molecular factories.

Nitroxide-containing amphiphilic polymers for therapeutic use were prepared in two-step procedure. Firstly, amphiphilic copolymers composed of hydrophobic poly(n -butyl acrylate) (P n BA) and hydrophilic poly[oligo(ethylene glycol) methyl ether acrylate] (POEGA) or poly(2-hydroxyethyl acrylate) (PHEA) were synthesized by simplified electrochemically mediated atom transfer radical polymerization (se ATRP). Due to the precisely-controlled structure of each polymer block proved by narrow dispersity (M w / M n < 1.19), chain-end halide functionality of macromolecules was preserved. Therefore, it was possible to efficiently convert the halide atom at the end of the chain to stable radicals via the amination of the polymer with 4-amino-2,2,6,6-tetrametylopiperydynyloksyl (4-amino-TEMPO, 4-AT). The prepared polymers are able to self-assemble in an aqueous solution into micelles with a hydrodynamic diameter of approximately 31 nm measured by dynamic light scattering (DLS) analysis. The susceptibility of the prepared micelles for biomedical applications was studied by evaluation of the effect on erythrocytes and fibroblasts and their antioxidant properties by testing of inhibition of oxidation reactions – oxidation of dihydrorhodamine 123 (DHR 123), induced by biologically relevant oxidants. The antioxidant effects of polymeric micelles were compared with those of free 4-AT. Prepared TEMPO-containing micelles exhibited biocompatibility in interaction with human erythrocytes and fibroblasts and exerted antioxidant effects. Therefore, the micelles are potentially good candidates for in vivo applications. [Display omitted] • Amphiphilic copolymers with highly preserved chain-end functionality were provided by se ATRP concept. • The precisely-controlled structure of each polymer block enables post-modification with 4-amino-TEMPO. • Polymeric micelles showed satisfactory biocompatibility and exerted antioxidant effects. • Nitroxide-containing polymer-based micelles have great potential for therapeutic use. [ABSTRACT FROM AUTHOR]

Membrane gas separation provides a multitude of benefits over alternative separation techniques, especially in terms of energy efficiency and environmental sustainability. While polymeric membranes have been extensively investigated for gas separations, their self-healing capabilities have often been neglected. In this work, we have developed innovative self-healing amphiphilic copolymers by strategically incorporating three functional segments: n -butyl acrylate (BA), N -(hydroxymethyl)acrylamide (NMA), and methacrylic acid (MAA). Utilizing these three functional components, we have synthesized two distinct amphiphilic copolymers, namely, AP NMA (PBA x - co -PNMA y ) and AP MAA (PBA x - co -PMAA y ). These copolymers have been meticulously designed for gas separation applications. During the creation of these amphiphilic copolymers, BA and NMA segments were selected due to their vital role in the ease of tuning mechanical and self-healing properties. The functional groups (-OH and -NH) present on the NMA segment interact with CO 2 through hydrogen bonding, thereby boosting CO 2 /N 2 separation and achieving superior selectivity. We assessed the self-healing potential of these amphiphilic copolymer membranes using two distinct strategies: conventional and vacuum-assisted self-healing. In the vacuum-assisted approach, a robust vacuum pump generates a suction force, leading to the formation of a cone-like shape in the membrane. This formation allows common fracture sites to adhere and trigger the self-healing process. As a result, AP NMA maintains its high gas permeability and CO 2 /N 2 selectivity even after the vacuum-assisted self-healing operation. The ideal CO 2 /N 2 selectivity of the AP NMA membrane aligns closely with the commercially available PEBAX-1657 membrane (17.54 vs 20.09). Notably, the gas selectivity of the AP NMA membrane can be readily restored after damage, in contrast to the PEBAX-1657 membrane, which loses its selectivity upon damage.

Copolymers of poly(ε-caprolactone) containing zwitterionic sulfobetaine may be used as biomedical materials. The interaction of these materials with proteins is rarely reported. In this study, amphiphilic copolymers PCL-PDEAS, PCL-PEG200-PDEAS, and PCL-PEG400-PDEAS, which contained poly{N-[2-(methacryloyloxy)ethyl]-N,N-diethyl-N-(3-sulfopropyl)-ammonium} (PDEAS), were designed and synthesized in order to explore interaction of these materials and their micelles with proteins. The structure of the copolymers was confirmed by H-NMR, Fourier transform infrared spectroscopy (FTIR), and element analysis (EA). The copolymers could form either films or micelles. The adsorption of bovine serum albumin (BSA) and fibrinogen (Fg) on the copolymer films and their micelles was studied. The results showed that BSA adsorbed on the films presented different tendencies from their micelle formulation. The protein adsorption may be related to the hydration in the shell of the micelles and the electrostatic interaction between the charges of zwitterion and the protein. The reason for the different amounts of protein adsorption between film and micelle formulation is the difference of molecular chain arrangement and charge distribution of PCLDEAS copolymer. [ABSTRACT FROM AUTHOR]

Amphiphilic block copolymers-based mixed micelles established as new drug-loading system showed superior characteristics in delivering drug such as improved solubility, enhanced stability, multifunctional carrier materials, targeting ability, and high bioavailability. Recently, there are increasing focuses on exploration and study of noninvasive routes, and the results present perfect feasibility, improved compliance and fewer aches and pains. The aim to apply mixed micelles to noninvasive alternative routes has driven massive pharmaceutical attention. Recently, various studies of micelles strategy for noninvasive routes have been conducted to overcome the inherent barriers for uptake across the gastrointestinal tract, mucosal membranes and other in vivo noninvasive barriers, and the result argues well. The objective of this article is to summary these studies and developments of mixed micelles used on noninvasive drug delivery and provide a reference for further research. [ABSTRACT FROM AUTHOR]

We report the computational analysis, synthesis and characterization of folate functionalized poly(styrene- alt -maleic anhydride), PSMA for drug delivery purpose. The selection of the proper linker between the polymer and the folic acid group was performed before conducting the synthesis using Density Functional Theory (DFT). The computational results showed the bio-degradable linker 2, 4-diaminobutyric acid, DABA as a good candidate allowing flexibility of the folic acid group while maintaining the pH sensitivity of PSMA, used as a trigger for drug release. The synthesis was subsequently carried out in multi-step experimental procedures. The functionalized polymer was characterized using InfraRed spectroscopy, Nuclear Magnetic Resonance and Dynamic Light Scattering confirming both the chemical structure and the pH responsiveness of PSMA-DABA-Folate polymers. This study provides an excellent example of how computational chemistry can be used in selection process for the functional materials and product characterization. The pH sensitive polymers are expected to be used in delivering anti-cancer drugs to solid tumors with overly expressed folic acid receptors. [ABSTRACT FROM AUTHOR]

Different types of amphiphilic macromolecular structures have been developed within recent decades to prepare the polymer particles considered as drug delivery systems. In the present research the series of amphiphilic block-copolymers containing poly(glutamatic acid) as hydrophilic, and polyphenylalanine as hydrophobic blocks was synthesized and characterized. Molecular weights for homo- and copolymers were determined by gel-permeation chromatography (GPC) and amino acid analysis, respectively. The copolymers obtained were applied for preparation of polymer particles. The specific morphology of prepared polymerosomes was proved using transmission electron microscopy (TEM). The influence on particle size of polymer concentration and pH used for self-assembly, as well as on the length of hydrophobic and hydrophilic blocks of applied copolymers, was studied by dynamic light scattering (DLS). Depending on different experimental conditions, the formation of nanoparticles with sizes from 60 to 350 nm was observed. The surface of polymersomes was modified with model protein (enzyme). No loss in biocatalytic activity was detected. Additionally, the process of encapsulation of model dyes was developed and the possibility of intracellular delivery of the dye-loaded nanoparticles was proved. Thus, the nanoparticles discussed can be considered for the creation of modern drug delivery systems. [ABSTRACT FROM AUTHOR]

We described the fabrication of functional and microstructured surfaces from polymer blends by spray deposition. This simple technique offers the possibility to simultaneously finely tune the microstructure as well as the surface chemical composition. Whereas at lower polymer concentration, randomly distributed surface micropatterns were observed, an increase of the concentration leads to significant changes on these structures. On the one hand, using pure homopolystyrene fiber-like structures were observed when the polymer concentration exceeded 30 mg/mL. Interestingly, the incorporation of 2,3,4,5,6-pentafluorostyrene changed the morphology, and, instead of fibers, micrometer size particles were identified at the surface. These fluorinated microparticles provide superhydrophobic properties leading to surfaces with contact angles above 165|. Equally, in addition to the microstructures provided by the spray deposition, the use of thermoresponsive polymers to fabricate interfaces with responsive properties is also described. Contact angle measurements revealed variations on the surface wettability upon heating when blends of polystyrene and polystyrene-b-poly(dimethylaminoethyl methacrylate) are employed. Finally, the use of spraying techniques to fabricate gradient surfaces is proposed. Maintaining a constant orientation, the surface topography and thus the contact angle varies gradually from the center to the edge of the film depending on the spray angle. [ABSTRACT FROM AUTHOR]

Poly ((ethylene oxide)- b-(propylene oxide)- b-(ethylene oxide)) triblock copolymers commonly known as poloxamers or Pluronics constitute an important class of nonionic, biocompatible surfactants. Here, a method is reported to incorporate two acid-labile acetal moieties in the backbone of poloxamers to generate acid-cleavable nonionic surfactants. Poly(propylene oxide) is functionalized by means of an acetate-protected vinyl ether to introduce acetal units. Three cleavable PEO-PPO-PEO triblock copolymers ( Mn,total = 6600, 8000, 9150 g·mol−1; Mn,PEO = 2200, 3600, 4750 g·mol−1) have been synthesized using anionic ring-opening polymerization. The amphiphilic copolymers exhibit narrow molecular weight distributions ( Ð = 1.06-1.08). Surface tension measurements reveal surface-active behavior in aqueous solution comparable to established noncleavable poloxamers. Complete hydrolysis of the labile junctions after acidic treatment is verified by size exclusion chromatography. The block copolymers have been employed as surfactants in a miniemulsion polymerization to generate polystyrene (PS) nanoparticles with mean diameters of ≈200 nm and narrow size distribution, as determined by dynamic light scattering and scanning electron microscopy. Acid-triggered precipitation facilitates removal of surfactant fragments from the nanoparticles, which simplifies purification and enables nanoparticle precipitation 'on demand.' [ABSTRACT FROM AUTHOR]

The dispersion of carbon nanoparticles in water was investigated using dispersants based on block copolymers of poly(acrylic acid) (PAA) and poly(amideimide) (PAI) or a homopolymer of PAA. A diblock copolymer (PAA- block-PAI), triblock copolymer (PAA- block-PAI- block-PAA), and hetero-arm star block copolymer (PAAPAI) with similar molecular weights and PAA contents were used as dispersants. The dispersion of solutions with these polymers was investigated by ζ-potential measurements and transmission electron microscopy. The adsorption of PAI onto carbon nanoparticles was observed. The dispersion of carbon nanoparticles was measured using dynamic light scattering and UV-vis spectroscopy. The dispersibility of carbon nanoparticles increased through the series of copolymers (from most to least dispersed): PAAPAI, PAA- block-PAI, PAA- block-PAI- block-PAA, and homo-PAA. PAA-PAI copolymers behaved as effective dispersants for carbon nanoparticles in water. The presence of a hydrophobic block was essential for dispersion. The architecture of the block copolymers also influenced the dispersion of nanoparticles. Locally concentrated regions of PAA exhibited repulsive interactions, causing dispersion of nanoparticles. PAAPAI demonstrated the greatest potential as an anode binder in lithium-ion batteries because it functioned as a dispersant for the conductive additive. [ABSTRACT FROM AUTHOR]

The oxidative coupling of 4- tert-butylphenol ( 1), 2,6-di- tert-butyl- p-cresol ( 11) and 4-cyanophenol ( 10) in the presence of iron salen catalysts (salen = N, N′-bis(salicylidine)ethylenediamine) and the influence of amine additives on the conversion of 1 were investigated. Furthermore, the activity of the iron complexes was correlated with the substituents at the 5,5′-positions of the salen ligands. Mechanistically conclusions based on dimer formation in the reaction between 10 and 11 are presented. In the second part of the study the obtained hydrophobic poly(4- tert-butylphenol) was modified with Jeffamine® M-600, M-1000 or M-2070 to give amphiphilic copolymers (18a-c). The amphiphilic copolymers were characterized via size-exclusion chromatography and dynamic light scattering. The concentration dependence of the cloud point appearance in water of amphiphilic copolymer 18c was analysed via turbidity measurements. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this study, synthesis and characterization of magnetic nanocarriers are reported for drug delivery based on the amphiphilic di-block and tri-block copolymers of poly(ethylene glycol) (PEG) and poly(ε-caprolactone) (PCL) with surface modified super-paramagnetite Fe3O4 nanoparticles (magnetic nanoparticles (MNPs)). The synthesized block copolymers (methoxy poly(ethylene glycol) (mPEG)-PCL and PCL-PEG-PCL) were characterized by Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC), and their properties such as critical micelle concentration, hydrophilicity to lipophilicity balance, and hydrolytic degradation were investigated. The block copolymers were functionalized with terminal azide groups (mPEG-PCL(N3) and (N3)PCL-PEG-PCL(N3)), and magnetic Fe3O4 nanoparticles were surface modified with poly(acrylic acid) (PAA) and propargyl alcohol (MNP-PAA-C≡CH). Magnetic nanocarriers were synthesized by click reaction between azide-terminated block copolymers and MNP-PAA-C≡CH and characterized by FT-IR, thermogravimetric analysis (TGA), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), and transmission electron microscopy (TEM), and cytotoxicity was investigated by methyl thiazolyl tetrazolium assay. In vitro drug loading and release and release kinetics were investigated. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

β-carotene, a potent antioxidant, has been encapsulated and slow release (SR) formulations were prepared using laboratory synthesized poly(ethylene glycols) (PEGs) based functionalized amphiphilic copolymers. Encapsulation efficiency and loading capacity of the developed formulations were determined which ranged from 22.60 to 28.08 % and 2.2 to 2.8 % respectively. The release kinetics of β-carotene from developed formulations in water revealed increased solubility and prolonged stability of β-carotene. The formulations were further subjected to different pH conditions (viz., 1.8, 6.8 and 7.8) corresponding to human gastrointestinal tract to study the effect of pH on the release of β-carotene. The diffusion exponent (n values) ranged from the 0.1540 to 0.2342 for developed formulation . The results showed that developed slow release formulations were unaffected by the highly acidic conditions referring to the gastric environment of human body. However, the release of β-carotene was high at pH 7.8 and slightly higher at pH 6.8. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis and characterization of Au and Ag nanoparticles prepared by direct reaction between poly(ethylene glycol)–poly(ε-caprolactone) (PEG–PCL) block copolymers and metal precursors in DMSO at 343 K. Special attention is devoted to the structural and molecular weight effects on nanoparticle synthesis to establish general correlations between the experimental parameters and the characteristics of the obtained nanoparticles. The noble metal nanoparticles were characterized by transmission electronic microscopy (TEM), dynamic light scattering (DLS), UV–visible spectroscopy, zeta potential (ZP) and FT-IR techniques. The shape and size of the obtained nanoparticles primarily depend mainly on the chemical structure and composition (PEG–PCL) of the copolymers used in the synthesis. From density functional theory (DFT), the chemical groups responsible for metal salt reduction and stabilization of the nanoparticles have been represented using simple models. The possible solvent effects were also considered by incorporation of a polarizable continuum model (PCM) into the calculations. [ABSTRACT FROM AUTHOR]

New amphiphilic block copolymers Si-EFS x composed of a poly(dimethyl siloxane) (Si) block and a poly(4-(triethyleneglycol monomethyl ether)-2,3,5,6-tetrafluorostyrene) (EFS) block are synthesized by atom transfer radical polymerization (ATRP) starting from a bromo-terminated Si macroinitiator. Similarly, new hydrophobic block copolymers Si-FS y consisting of an Si block and a poly(pentafluorostyrene) (FS) block are prepared for comparison. X-ray photoelectron spectroscopy (XPS) analysis on block copolymer films reveals that the Si block is concentrated at the polymer-air interface, while the EFS block is located in the layers underneath. The same polymer films undergo a marked surface reconstruction after immersion in water for 7 d, as probed by XPS. This phenomenon involves the exposure of the hydrophilic oxyethylenic chains to contact water. Such surface reconstruction is even more drastic when an amphiphilic block copolymer is dispersed in a cross-linked poly(dimethyl siloxane) matrix film. [ABSTRACT FROM AUTHOR]

Poly(ethylene oxide)- block -poly(methyl methacrylate) amphiphilic copolymers were prepared via electrochemically mediated atom transfer radical polymerization ( e ATRP) utilizing only 50 ppm of Cu II complex, rather than previously reported concentrations of catalyst of ca. 1,000–30,000 ppm. The copolymers were also prepared via a simplified electrochemically mediated ATRP ( se ATRP) procedure utilizing an aluminum wire sacrificial anode as a counter electrode, which was directly immersed into the reaction flask, without the need of its separation. This se ATRP system works under both potentiostatic and galvanostatic conditions. In each case the polymerization results showed similar molecular weight evolution while maintaining a narrow molecular weight distribution throughout the reactions. The successful chain extension and formation of block copolymers confirmed the living nature of the poly(alkyl methacrylates) prepared by e ATRP and se ATRP. [ABSTRACT FROM AUTHOR]

Atom Transfer Radical Polymerization (ATRP) and Ring-Opening Polymerization (ROP) were combined to synthesize diblock environmental friendly poly(ϵ-caprolactone)-block-poly(methyl ether diethylene glycol methacrylate) (PCL- b -PMEO 2 MA) through a sequential two-step strategy. These PCL- b -PMEO 2 MA copolymers were produced using 2-hydroxyethyl-2-bromoisobutyrate as bifunctional initiator. In the first step, ϵ-caprolactone was initiated by the hydroxyl group of this particular initiator. Tin octoate, zinc triflate and bismuth triflate were tested as non-toxic catalysts to obtain α-bromide–ω-hydroxy bifunctional PCL macroinitiator. Secondly, the controlled ATRP of MEO 2 MA was tuned from the same bifunctional initiator. Finally, PCL- b -PMEO 2 MA were produced by carrying out ATRP of MEO 2 MA from PCL macroinitiator. Preliminary data on self-assembly of such thermo-sensitive PCL- b -PMEO 2 MA in aqueous phase are given. [ABSTRACT FROM AUTHOR]

This work introduces a new polymeric emulsifier, polyglycerol- block-poly(ε-caprolactone), to prepare and stabilize oil-in-water nanoemulsions through the formation of a semi-solid interphase between oil and water. Nanoemulsions are prepared using representative silicone and ester oils, which are widely used for commercial consumer products. The block copolymer is homogeneously solubilized in a mixture of oil and ethanol at 70 °C, and the organic solution is dispersed in water using a conventional homogenizer. Stable nanoemulsions of 220-280 nm in mean diameter are spontaneously generated. The block copolymer is reorganized at the interface to form a robust semi-solid polymeric barrier that can prevent the entrapped oil from diffusing out to the aqueous phase. The barrier exhibits excellent stability against mechanical stresses, allowing nanoemulsions to be very stable during repeated freeze/thaw cycles. This work suggests that polyglycerol-based block copolymers can be a new promising polymeric emulsifier for stabilization of nanoemulsions of various oils. [ABSTRACT FROM AUTHOR]

Multicomponent segmented polyurethanes ( SPUs) based on poly(ethylene glycol), poly( l-lactide) and poly(trimethylene carbonate) as macrodiols, 2,4-toluene diisocyanate (2,4- TDI) or 1,6-hexane diisocyanate ( HDI) as diisocyanate, and 1,4-butanediol ( BDO) or 2,2-bis(hydroxymethyl)propionic acid ( DMPA) as chain extenders were synthesized. The molecular, thermal, dynamic mechanical and morphological features of this set of uncrosslinked polyurethanes are characterized using 1H NMR, gel permeation chromatography, differential scanning calorimetry, dynamic mechanical thermal analysis ( DMTA) and atomic force microscopy techniques. The lower reaction rate of HDI in comparison with 2,4- TDI allows for better control of the SPU compositions, so that the intrinsic properties of each block can be better combined and modulated. HDI-based SPUs are semi-crystalline, while those based on 2,4- TDI are amorphous, affecting the mechanical properties of these polyurethanes. All SPUs are heterogeneous, presenting morphologies of a disperse phase in a matrix which varies with the macrodiol ratios as well as with the nature of the diisocyanate and chain extender (a finer dispersion of the disperse phase is observed for SPUs of HDI and BDO). DMTA results indicate that the phases are complex mixtures of the different blocks with at least one rich in PLLA. The PEG content is shown to be the most important factor influencing the water sorption capability, while the incorporation of hindering carboxylic acid groups by the use of DMPA allows the water uptake of SPUs to be controlled by the solution pH. All SPUs show a significant loss of molar mass in hydrolytic degradation experiments and, in general, the PLLA-rich SPUs are more susceptible to degradation. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Poly (diethyl vinylphosphonate-co-2-chloroethyl methacrylate) (P(DEVP-co-CEMA)) copolymers are synthesized by free radical copolymerization initiated by benzoyl peroxide. The reactivity ratios for the free radical copolymerization of CEMA (M1) and DEVP (M2) arer1 = 19.45 andr2 = 0.11, respectively. The desired amphiphilic copolymers with relatively low polydispersity index (PDI) and different DEVP contents are isolated and purified from the reaction mixtures through precipitation fractionation. The structures and molecular characteristics of the obtained products are characterized by1H NMR, FTIR, and SEC analysis. All of these fractionated copolymers have a unimodal distribution and moderate PDI. The thermal properties of the P(DEVP-co-CEMA) copolymers are investigated by TGA and differential scanning calorimetry (DSC) measurements. Single glass transition temperature (Tg) appears in the DSC profiles differing from the existence of twoTgs in the blend of poly (diethyl vinylphosphonate) and poly (2-chloroethyl methacrylate), which indicates the random structure of the copolymers. The MALDI–ToF mass analysis further reveals that DEVP and CEMA units are randomly distributed in the copolymer chains. The self-assembly behavior of the P(DEVP-co-CEMA) copolymers in aqueous solution is preliminarily investigated. [ABSTRACT FROM AUTHOR]

Microbial biofilms are known to support a number of human infections, including those related to medical devices. This work is focused on the development of novel dual-function amphiphilic random copolymers to be employed as coatings for medical devices. Particularly, copolymers were obtained by polymerization of an antimicrobial cationic monomer (bearing tertiary amine) and an antioxidant and antimicrobial hydrophobic monomer (containing hydroxytyrosol, HTy). To obtain copolymers with various amphiphilic balance, different molar ratios of the two monomers were used. 1 H NMR and DSC analyses evidenced that HTy aromatic rings are able to interact with each other leading to a supra-macromolecular re-arrangement and decrease the copolymer size in water. All copolymers showed good antioxidant activity and Fe 2+ chelating ability. Cytotoxicity and hemolytic tests evidenced that the amphiphilic balance, cationic charge density and polymer size in solution are key determinants for polymer biocompatibility. As for the antimicrobial properties, the lowest minimal inhibitory concentration (MIC = 40 μg/mL) against Staphylococcus epidermidis was shown by the water-soluble copolymer having the highest HTy molar content (0.3). This copolymer layered onto catheter surfaces was also able to prevent staphylococcal adhesion. This approach permits not only prevention of biofilm infections but also reduction of the risk of emergence of drug-resistant bacteria. Indeed, the combination of two active compounds in the same polymer can provide a synergistic action against biofilms and suppress reactive species oxygen (ROS), known to promote the occurrence of antibiotic resistance. [ABSTRACT FROM AUTHOR]

ABSTRACT Four families of hyperbranched amphiphilic block copolymers of styrene (Sty, less polar monomer) and 2-vinylpyridine (2VPy, one of the two more polar monomers) or 4-vinylpyridine (4VPy, the other polar monomer) were prepared via self-condensing vinyl reversible addition-fragmentation chain transfer polymerization (SCVP-RAFT). Two families contained 4VPy as the more polar monomer, one of which possessing a Sty -b-4VPy architecture, and the other possessing the reverse block architecture. The other two families bore 2VPy as the more polar monomer and had either a 2VPy -b-Sty or a Sty -b-2VPy architecture. Characterization of the hyperbranched block copolymers in terms of their molecular weights and compositions indicated better control when the VPy monomers were polymerized first. Control over the molecular weights of the hyperbranched copolymers was also confirmed with the aminolysis of the dithioester moiety at the branching points to produce linear polymers with number-average molecular weights slightly greater than the theoretically expected ones, due to recombination of the resulting thiol-terminated linear polymers. The amphiphilicity of the hyperbranched copolymers led to their self-assembly in selective solvents, which was probed using atomic force microscopy and dynamic light scattering, which indicated the formation of large spherical micelles of uniform diameter. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1310-1319 [ABSTRACT FROM AUTHOR]

In previous works, poly(D,L-lactide-co-εCL-poly(ethylene glycol) (poly(D,L-La-co-αPEGεCL) amphiphilic graftcopolymers were successfully synthesized according to a copper azide-alkyne cycloaddition (CuAAC) strategy. This paper aims at reporting on the behavior of this amphiphilic copolymer in water, which was not studied in the previous paper. Moreover, the ability of the copolymer to stabilize a PLA nanoparticles aqueous suspension is presented. For this purpose, dynamic light scattering (DLS) and transmission electron microscopy (TEM) are proposed to characterize the nanoparticles in solution. Otherwise, the strategy developed for the synthesis of the amphiphilic copolymers was adapted and extended to the synthesis of PLA-based degradable hydrogel, potentially applicable as drug-loaded degradable polymer implant. [ABSTRACT FROM AUTHOR]

Casein-based emulsion for film former was innovatively prepared via emulsifier-free emulsion polymerization by employing self-made amphiphilic copolymers (A m B n C o ) as the stabilizer. Structure of A m B n C o was confirmed by 1 H NMR spectrometry. Stability of the as-prepared emulsion in different concentrations of A m B n C o was evaluated by measuring their droplet size, microstructure and viscosity. The results indicated that the obtained particles were 40–50 nm in size with uniform size distribution, and exhibited obvious core–shell structure. The emulsion containing 1.0 wt% of A m B n C o presented superior storage stability. [ABSTRACT FROM AUTHOR]

Oil-in-water (O/W) emulsions are generally stabilized by water-soluble surfactants, which anchor to the surface of oil droplets dispersed in an aqueous solution. Our recent work introduced a new approach to stabilize nanoemulsions through the formation of a semi-solid interphase at the O/W interface using a water-insoluble amphiphilic block copolymer, methoxy poly(ethylene glycol)- block -poly(ɛ-caprolactone). However, the approach is not applicable to relatively non-polar oils due to the quick precipitation of the hydrophobic PCL block within the oil phase. Here we report on successful stabilization of non-polar liquid paraffin nanoemulsions using an amphiphilic copolymers having a new hydrophobic block comprising ɛ-caprolactone and L -lactide. The new block copolymer was reorganized at the O/W interface of liquid paraffin, generating stable nano-sized emulsions via the formation of a robust semi-solid polymeric barrier. The prepared nanoemulsions show excellent dispersion stability even under a high level of mechanical stresses during freeze/thaw cycles. [ABSTRACT FROM AUTHOR]

Polymeric micelles functionalized with folate conjugated bovine serum albumin (FA-BSA) and loaded with superparamagnetic iron oxide nanoparticles (SPIONs) are investigated as a specific contrast agent for tumor targeting and magnetic resonance imaging (MRI) in vitro and in vivo . The SPIONs-loaded polymeric micelles are produced by self-assembly of amphiphilic poly(HFMA-co-MOTAC)-g-PEGMA copolymers and oleic acid modified Fe 3 O 4 nanoparticles and functionalized with FA-BSA by electrostatic interaction. The FA-BSA modified magnetic micelles have a hydrodynamic diameter of 196.1 nm, saturation magnetization of 5.5 emu/g, and transverse relaxivity of 167.0 mM −1 S −1 . In vitro MR imaging, Prussian blue staining, and intracellular iron determination studies demonstrate that the folate-functionalized magnetic micelles have larger cellular uptake against the folate-receptor positive hepatoma cells Bel-7402 than the unmodified magnetic micelles. In vivo MR imaging conducted on nude mice bearing the Bel-7402 xenografts after bolus intravenous administration reveals excellent tumor targeting and MR imaging capabilities, especially at 24 h post-injection. These findings suggest the potential of FA-BSA modified magnetic micelles as targeting MRI probe in tumor detection. [ABSTRACT FROM AUTHOR]

2D/3D structures resulting from self-assembly of amphiphilic block copolymers can be combined with bioactive compounds, such as proteins and enzymes, to create supramolecular assemblies with specific desired properties and functionality. Chemical tuning of the architecture and properties of supramolecular assemblies to accommodate sensitive biomolecules allows the development of new soft hybrid materials that benefit from the robustness of polymers and from the functionality of biomolecules. The encapsulation/insertion of biomolecules (enzymes, mimics, proteins) in self-assembling block copolymer vesicles enables design of 'nanoreactors' both in solutions and at surfaces for highly diverse applications, ranging from production of antibiotics to creation of artificial organelles. When membrane proteins are inserted into polymer membranes, it is possible to generate functional membranes or active surfaces with a rapid and specific response. In addition, the selective binding of ligand-terminated polymers holds potential for targeted delivery of drugs, or for immobilization on solid support, to provide functional 3D assemblies on an extended surface.

One of the most pervasive environmental issues is water contaminated with oil or organic solvents; this global challenge calls for emerging materials that could effectively separate oil or organic solvents from water. Here, such a material is presented by integrating 3D porous graphene foam (GF) with a smart pH-responsive surface, showing switchable superoleophilic and superoleophobic properties in response to the medium pH. The key chemistry applied in this study is to modify the 3D porous GF with an amphiphilic copolymer containing a block of poly(2-vinylpyridine) and polyhexadecyl acrylate (P2VP -b-PHA), resulting in a smart GF ( ss-GF) with an either superoleophilic or superoleophobic surface at different medium pH. The as-designed ss-GF can effectively absorb oil or organic solvents from the aqueous media by using its superoleophilic surface at pH of 7.0, and it can also completely release the adsorbates when the pH is switched to 3.0 (and the surface of ss-GF is therefore shifted to superoleophobic); with a continuous operation of many cycles (e.g., >10). Furthermore, the as-designed ss-GF shows superior absorption capacity for oil and organic solvent, with a high capacity of ≈196 times of the weight relative to that of the pristine ss-GF. The present work suggests encouraging applications of the ss-GF to water-oil and water-organic solvent separation. [ABSTRACT FROM AUTHOR]

Binary and ternary segmented polyurethanes (SPU) based on low molar mass (2 kDa) homopolymers – poly(ethylene glycol), poly( l -lactide) and poly(trimethylene carbonate) (PEG, PLLA and PTMC, respectively) – and 2,4-toluene diisocyanate were synthesized using 1,4-butanediol and dibutyltin dilaureate as the chain extender and catalyst, respectively. Rigorous control of the OH/NCO stoichiometry and temperature allowed the synthesis of sixteen uncrosslinked polyurethanes with modulated compositions and properties. The molecular characterizations of the SPUs were performed using 1 H NMR and GPC, and the thermal, dynamic mechanical and morphological features were investigated using DSC, DMTA and AFM, respectively. The blocks were randomly distributed in the polymer chains, which resulted in suppression of the crystallization of the blocks in most of the SPUs. The binary and ternary SPUs are heterogeneous, presenting morphologies of dispersed phase in a matrix, whose compositions depend on the global composition. The hydrophilicity of the SPUs were evaluated using water swelling experiments, and the hydrophilic/hydrophobic balance of the SPUs can be controlled by altering the composition to achieve a completely water soluble SPU (in PEG-rich SPUs), a higher water uptake capability, resulting in a hydrogel (intermediate composition), or a non-swellable polymer (PLLA-PTMC binary SPUs). The dependence of water uptake on temperature was observed mainly in PEG-rich SPUs. The intrinsic properties of each block, such as the hydrophilicity of PEG, stiffness of PLLA and elasticity of PTMC, are combined and modulated in the SPUs. PTMC confers unique properties to ternary SPUs owing to its partial miscibility with both PEG and PLLA. [ABSTRACT FROM AUTHOR]

An effective liver-targeted delivery system was successfully developed by designing ligand-mediated nanoparticles composed of glycyrrhetinic acid (GA)-conjugated block copolymers (glycyrrhetinic acid-modified poly(ethylene glycol)-poly(β-benzyl- l-asparate, GA-PEG-PBLA) synthesized via ring-opening polymerization of the β-benzyl- l-asparate N-carboxyanhydride (BLA-NCA) monomer initiated by GA-modified polyethylene glycol (PEG). Chemical structures of the synthesized polymers were confirmed by H nuclear magnetic resonance (H NMR) and Fourier transform infrared assay (FTIR) and molecular weight determined by gel permeation chromatography (GPC). The copolymers were processed into nanoparticles for delivery of paclitaxel (PTX). In this work, the PTX-loaded nanoparticles were prepared by the emulsion-solvent evaporation method, and the physicochemical properties and cytotoxicity were investigated. The particle sizes of nanoparticles determined by dynamic light scattering measurements were around 70 nm. Transmission electron microscopy showed that the nanoparticles were spherical in shape. The results of in vitro release tests showed that the release profiles of PTX-loaded nanoparticles had a sustained drug release pattern, and PTX release from nanoparticles at pH 5.8 was much faster than that at pH 7.4. The drug release profiles were also fitted for mathematical models to analyze the release mechanism, and the Korsmeyer-Peppas model was found to be the best fit model, indicating a combined effect of diffusion and erosion mechanisms for drug release. The cytotoxicity based on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against human hepatic carcinoma HepG2 cells indicated that the GA-PEG-PBLA nanoparticles had low cytotoxicity and good biocompatibility. These results indicated that the GA-PEG-PBLA nanoparticles could be a novel candidate for liver-targeted delivery of poorly water-soluble anticancer drugs. [ABSTRACT FROM AUTHOR]

In this work, TiO 2 nanoparticles were dispersed and stabilized in water using a novel type of dispersant based on tailor-made amphiphilic block copolymers of poly(ethylene glycol)-block-poly(4-vinyl pyridine) (mPEG- b -P4VP) prepared by atom transfer radical polymerization (ATRP). The performance of this new block copolymer as dispersant was compared to a polyelectrolyte dispersant commonly used for TiO 2 , sodium salt of polyacrylic acid (Na-PAA). The effect of dispersion technique and type and amount of dispersant on deagglomeration and stability of the TiO 2 aqueous suspensions were studied. After incorporation in a standard waterborne acrylic varnish formulation, dry film transparency, photocatalytic activity, and nanoparticle cluster size were also evaluated. The results show that mPEG- b -P4VP copolymer with appropriate block lengths can have a better performance than Na-PAA in terms of aqueous dispersion stabilization and cluster size reduction in the acrylic matrix. This translates into higher film transparency and photocatalytic performance. [ABSTRACT FROM AUTHOR]

A simple 'green synthesis' of noble metal nanoparticles by direct reaction between Dextran-graft-lactone copolymers and metal salts without the need to separately add reducing and stabilizing agents was carried out. The effects of the composition, molecular weights of copolymers and solvents on the characteristics of the nanoparticles were considered. The amphiphilic character of the copolymers seems to be an important factor in the results of the synthesis. According to the results, general correlations between experimental parameters of synthesis and characteristics of the obtained nanoparticles were established. Techniques such as, transmission electron microscopy, scanning electron microscopy, UV-visible spectroscopy, Zeta Potential, dynamic light scattering and Fourier transform Infrared Spectroscopy, were used for the characterization of the products. The results indicate the possibility of control of the characteristics of the nanostructured material. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The physicochemical properties of "smart" or stimuli-sensitive amphiphilic copolymers can be modeled as a function of their environment. In special, pH-sensitive copolymers have practical applications in the biomedical field as drug delivery systems. Interactions between the structural units of any polymer-drug system imply mutual constraints at various scale resolutions and the nonlinearity is accepted as one of the most fundamental properties. The release kinetics, as a function of pH, of a model active principle, i.e., Curcumin, from nanomicelles obtained from amphiphilic pH-sensitive poly(2-vinylpyridine)-b-poly(ethylene oxide) (P2VP-b-PEO) tailor-made diblock copolymers was firstly studied by using the Rietger-Peppas equation. The value of the exponential coefficient, n, is around 0.5, generally suggesting a diffusion process, slightly disturbed in some cases. Moreover, the evaluation of the polymer-drug system's nonstationary dynamics was caried out through harmonic mapping from the usual space to the hyperbolic one. The kinetic model we developed, based on fractal theory, fits very well with the experimental data obtained for the release of Curcumin from the amphiphilic copolymer micelles in which it was encapsulated. This model is a variant of the classical kinetic models based on the formal kinetics of the process.

[Display omitted] • RAFT polymerization of well-defined coumarin bearing amphiphilic copolymers. • Coumarin functionalized unique amphiphilic copolymers as repeating units on the chain. • Temperature responsive Pluronic F127 with light-responsive amphiphilic copolymers. • Designing mechanically strong injectable PF127 hydrogels. Temperature responsive Pluronic F127 micelles were combined with light-responsive coumarin bearing amphiphilic copolymers to obtain both mechanically strong and injectable gels. For this purpose two monomers, 7-(2-methacryloyloxyethoxy)-4-methylcoumarin (CEMA) and 7-methacryloyloxy-4-methylcoumarin (CMA), were synthesized and further polymerized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Well-defined amphiphilic diblock terpolymers were obtained by using preliminarily synthesized polyethylene glycol (PEG) based macroRAFT agent. The structures of copolymers were confirmed with proton nuclear magnetic resonance spectroscopy (1H NMR), Fourier-transform infrared (FT-IR) spectroscopy and gel permeation chromatography (GPC) analyses. Amphiphilic diblock terpolymers self-assembled into micelles in aqueous solution spontaneously and crosslinking of the micelle cores through the photodimerization of coumarin groups under UV irradiation at 350 nm was examined by UV spectroscopy. Hydrogels were prepared using two different methods, PF127-Mx gels formed using polymer micelle solutions with PF127 solid and PF127-Px gels formed by mixing solid polymers with 20 % F127 solution. Upon characterization of hydrogels via dynamic light scattering (DLS) and transition electron microscope (TEM), rheological properties of the gels were evaluated as a function of temperature, composition, UV exposure time, strain and frequency. Injectability tests of hydrogel systems were performed on a texture analyzer and all the formulations were found in the injectable range. The study reveals that hydrogels based on combination of PF127 and coumarin functional terpolymer amphiphiles hold great potential as injectable biomaterials. [ABSTRACT FROM AUTHOR]