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Natural single‐chain nanoparticles (SCNPs) such as proteins have inspired research into the formation and application of synthetic SCNPs. Although the latter can mimic general aspects of the self‐assembly behavior of their biological counterparts, these systems remain relatively understudied. In this respect, a systematic series of amphiphilic statistical copolymers (ASC) of different molecular weights, with a hydrophilic comonomer (methacrylic acid) and varying hydrophobic comonomer to encompass methacrylates of different hydrophobicity, are synthesized. Small‐angle X‐ray scattering studies confirmed that SCNPs are achieved for each copolymer series when dispersed in basified water at 1% w/w. When the aggregation number of the ASC nanoparticles is close to unity the particle shape elongates resulting in a larger particle surface area to volume ratio, allowing more hydrophilic groups to locate on the particle surface tending to keep the particle surface charge density (PSC) constant. Thus, within a series, particle elongation increases with copolymer molecular weight. Structural parameters of SCNPs formed by ASCs composed of hydrophobic components with low partition coefficients are well consistent with predictions obtained from the PSC model. These results highlight the main parameters, namely molecular weight and acid content, responsible for the SCNP formation and provide insight into how specific particle morphology can be targeted. [ABSTRACT FROM AUTHOR] more...

We have constructed the phase diagrams in water of two commercial additives for coatings consisting of polyether‐modified polydimethylsiloxanes. These aqueous systems form a liquid crystal mesophase (LC) at copolymer concentrations higher than 60 wt%. At low copolymer concentrations, this LC coexists with a diluted aqueous phase. Small angle x‐ray scattering (SAXS) measurements and polarized optical microscope observations indicate that the structure of the mesophase is lamellar, with an interlayer spacing that increases linearly with the concentration of water in the system. The lamellar liquid crystals display temperature‐dependent viscoelastic behavior, with the copolymer with longer spacing showing a much lower elastic modulus. Since one of the copolymer has terminal acryl groups, its lamellar phase can be crosslinked to produce gelled liquid crystals. Other cross‐linked self‐assembled structures, such as bicontinuous microemulsions, are envisaged. [ABSTRACT FROM AUTHOR] more...

This study focused on synthesizing and characterizing PEGylated amphiphilic block copolymers with pendant linoleic acid (Lin) moieties as an alternative to enhance their potential in drug delivery applications. The synthesis involved a two‐step process, starting with ring‐opening polymerization of ε‐caprolactone (CL) and propargylated cyclic carbonate (MCP) to obtain PEG‐b‐P(CL‐co‐MCP) copolymers, which were subsequently modified via click chemistry. Various reaction conditions were explored to improve the yield and efficiency of the click chemistry step. The use of anisole as a solvent, N‐(3‐azidopropyl)linoleamide as a substrate, and a reaction temperature of 60°C proved to be highly efficient, achieving nearly 100% conversion at a low catalyst concentration. The resulting copolymers exhibited controlled molecular weights and low polydispersity, confirming the successful synthesis. Furthermore, click chemistry allows for the attachment of Lin moieties to the copolymer, enhancing its hydrophobic character, as deduced from their significantly lower critical micelle concentration than that of traditional PEG‐b‐PCL systems, which is indicative of enhanced stability against dilution. The modified copolymers exhibited improved thermal stability, making them suitable for applications that require high processing temperatures. Dynamic light scattering and transmission electron microscopy confirmed the formation of micellar structures with sizes below 100 nm and minimal aggregate formation. Additionally, 1H NMR spectroscopy in deuterated water revealed the presence of core‐shell micelles, which provided higher kinetic stability against dilution. [ABSTRACT FROM AUTHOR] more...

Giant unilamellar vesicles (GUVs) are microcompartments serving to confine reactions, allow signaling pathways, or design synthetic cells. Polymer GUVs are composed of copolymer membranes mimicking cell membranes, and present advantages over lipid-based GUVs, such as higher mechanical stability and chemical versatility. Such microcompartments are essential for understanding reactions/signaling occurring in cells, which are difficult to study by in vivo approaches due to the cell's complexity. However, the lack of control over their production, stability, and membrane diffusion properties is still limiting their use for bio-related applications. Here, polymer GUVs produced by microfluidics and permeabilized with DNA-origami nanopores (DoNs) that present a high level of control over these essential properties are introduced. After systematic optimization of conditions, DoN-GUVs reveal a narrow size distribution, allow for high encapsulation efficiencies, and are stable for weeks, protecting encapsulated biomolecules. The kinetics of diffusion of molecules through the GUV's membrane is tuned by insertion of DoNs with a controlled 3D-structure. DNA polymerase I, encapsulated as model for bioreactions, successfully produced DNA duplex strands with spatiotemporal control. DoN-GUVs loaded with active molecules open new avenues in bioreactions, from the detection of biomolecules, over the tuning of molecular transport rates, to the investigation of cellular processes/signaling. [ABSTRACT FROM AUTHOR] more...

Synthetic anion transporters are potential therapeutics for a plethora of cellular ailments including cystic fibrosis, cancer resistance, epilepsy, etc. In this context, cationic macromolecular amphiphiles are gaining revived interest because of their easy synthesis and ample ion channelization through the membrane barrier. Herein, side chain alanine containing cationic polymer amphiphiles with steroid/fatty acid decoration was established to be an efficient anion‐selective artificial ionophore. The facile amphiphilicity‐assisted assembly makeover of cholic acid containing copolymers channelized the better transmembrane anion transport and efficiency with the maximum selectivity found with NO2− ion. [ABSTRACT FROM AUTHOR] more...

Hydrophilic chitosan (CHT) and hydrophobic polyε‐caprolactone (PCL) are well‐known biocompatible and biodegradable polymers that have many applications in the biomedical and pharmaceutical fields. But the mixtures of these two compounds are considered incompatible, which makes them not very interesting. To avoid this problem and to further extend the properties of these homopolymers, the synthesis of a new graft copolymer, the fully biodegradable amphiphilic poly(ε‐caprolactone‐g‐chitosan) (PCL‐g‐CHT) is described, with an unusual "reverse" structure formed by a PCL backbone with CHT grafts, unlike the "classic" CHT‐g‐PCL structure with a CHT main chain and PCL grafts. This copolymer is prepared via a copper‐catalyzed 1,3‐dipolar Huisgen cycloaddition between propargylated PCL (PCL‐yne) and a new azido‐chitosan (CHT‐N3). In order to obtain an amphiphilic copolymer regardless of the pH, chitosan oligomers, soluble at any pH, are prepared and used. The amphiphilic PCL‐g‐CHT copolymer spontaneously self‐assembles in water into nanomicelles that may incorporate hydrophobic drugs to give novel drug delivery systems. [ABSTRACT FROM AUTHOR] more...

In this work, amphiphilic polymers synthesized from carboxylated carbon nanotubes stabilized high internal phase emulsions are demonstrated to be capable of direct extracting zearalenone and zearalanone in samples consisting of an oil‐water emulsion system. Under optimal conditions, the maximum adsorption capacities for zearalenone and zearalanone are 17.27 and 13.26 mg/g. The adsorption is mainly attributed to π‐π interaction, hydrophobic interaction, and hydrogen‐bonding interaction for zearalenone and zearalanone. The adsorption isotherms reveal that the adsorption of zearalenone and zearalanone on amphiphilic polymers synthesized from carboxylated carbon nanotubes stabilized high internal phase emulsions follows Freundlich model with multilayer and heterogeneous adsorption due to the presence of multiple kinds of adsorption sites. The relative recoveries of the spiked zearalenone and zearalanone in corn juice samples range from 85% to 93% with relative standard deviations lower than 3.52%. The results manifest the high efficiency of amphiphilic polymers synthesized from carboxylated carbon nanotubes stabilized high internal phase emulsions for the adsorption and separation of analytes in the oil‐water emulsion system. This study provides a new perspective on adsorbent engineering for the adsorption application in heterogeneous media. [ABSTRACT FROM AUTHOR] more...

Amphiphilic copolymers (AP) represent a class of novel antibiofouling materials whose chemistry and composition can be tuned to optimize their performance. However, the enormous chemistry‐composition design space associated with AP makes their performance optimization laborious; it is not experimentally feasible to assess and validate all possible AP compositions even with the use of rapid screening methodologies. To address this constraint, a robust model development paradigm is reported, yielding a versatile machine learning approach that accurately predicts biofilm formation by Pseudomonas aeruginosa on a library of AP. The model excels in extracting underlying patterns in a "pooled" dataset from various experimental sources, thereby expanding the design space accessible to the model to a much larger selection of AP chemistries and compositions. The model is used to screen virtual libraries of AP for identification of best‐performing candidates for experimental validation. Initiated chemical vapor deposition is used for the precision synthesis of the model‐selected AP chemistries and compositions for validation at solid–liquid interface (often used in conventional antifouling studies) as well as the air–liquid–solid triple interface. Despite the vastly different growth conditions, the model successfully identifies the best‐performing AP for biofilm inhibition at the triple interface. [ABSTRACT FROM AUTHOR] more...

By combining oppositely charged polydiallyldimethylammonium chloride (PDADMAC) and sodium polyacrylate (NaPA), interpolyelectrolyte complexes (IPECs) can be formed in aqueous solution. Such IPECs are studied for rather short NaPA and under variation of the Mw of PDADMAC. The focus is on elucidating the effect of having a hydrophobic modification of the NaPA, which is introduced by having 10 mol% of the monomeric units substituted by ones carrying a dodecyl alkyl chain. This modification renders the complexes more hydrophobic, which is seen in the fact that precipitation of the complexes occurs at a lower mixing ratio and the biphasic region is also wider. The structures of the soluble IPECs are studied by a combination of light and neutron scattering (SANS). It is observed that the complexes formed possess typical radii of gyration of ≈30–40 nm, which become somewhat smaller with increasing length of the PDADMAC chain. The SANS data can be described well with the Beaucage model for complexes, where locally small hydrophobic domains of cylindrical shape are formed, whose persistence length decreases with increasing content of NaPA in the complexes. In contrast no such structures are seen for NaPA without the hydrophobic modification. The cylindrical domains are then arranged within larger‐sized clusters of 30–40 nm, which become more compact with reduced length of the PDAMAC chains. The structure of the IPECs is largely determined by the presence of the hydrophobic modification of the NaPA and is further controlled by the length of the hydrophobic modification. Such IPECs of controlled structure, relatively small size, and containing hydrophobic domains are potentially interesting as delivery systems due to having domains of variable polarity. [ABSTRACT FROM AUTHOR] more...

Previous studies have demonstrated that films of sequence‐controlled amphiphilic copolymers display contact angles that depend on microblock size. This suggests that microblock length may provide a means of tuning surface and interfacial properties. In this work, the interfacial rheology of a series of sequence‐controlled copolymers, prepared through the addition of bicyclo[4.2.0]oct‐1(8)‐ene‐8‐carboxamide (monomer A) and cyclohexene (monomer B) to generate sequences up to 24 monomeric units composed of (AmBn)i microblocks, where m, n, and i range from 1 to 6. Interfacial rheometry is used to measure the mechanical properties of an air–water interface with these copolymers. As the microblock size increases, the interfacial storage modulus, G′, increases, which may be due to an increase in the size of interfacial hydrophobic domains. Small‐angle X‐ray scattering shows that the copolymers have a similar conformation in solution, suggesting that any variations in the mechanics of the interface are due to assembly at the interface, and not on solution association or bulk rheological properties. This is the first study demonstrating that microblock size can be used to control interfacial rheology of amphiphilic copolymers. Thus, the results provide a new strategy for controlling the dynamics of fluid interfaces through precision sequence‐controlled polymers. [ABSTRACT FROM AUTHOR] more...

This paper deals with the development of polymeric nanocarriers based on amphiphilic copolymers of N‐vinyl‐2‐pyrrolidone and acrylic acid of various molecular weights synthesized through the AIBN‐initiated radical copolymerization of N‐vinyl‐2‐pyrrolidone and acrylic acid in the presence of n‐octadecyl mercaptan. The structure of the copolymers is characterized by 1Н NMR, 13С NMR, IR and MALDI‐TOF MS spectroscopy. It is shown that the length of the hydrophilic block defines the size of the nanoaggregates while impacting the steric stabilization efficiency and the probability of the interchain hydrogen bond formation. The hydrogen bonds formation between the residues of N‐vinyl‐2‐pyrrolidone and acrylic acid is in agreement with the reduction of the ζ‐potential of the nanoaggregates and the critical aggregation concentrations upon increasing the molecular weight. The presence of acrylic acid residues in the amphiphilic macromolecules leads to a higher affinity for doxorubicin and slow partial release of doxorubicin bonded with the aggregates' corona, which is helpful for reducing its cardiac toxicity. Nanoaggregates with a paclitaxel‐loaded hydrophobic core are obtained, showing the possibility of dual loading. The amphiphilic copolymers of N‐vinyl‐2‐pyrrolidone and acrylic acid containing an n‐octadecyl thio end group are thus promising candidates for combination cancer therapy with immobilized anti‐cancer drugs, paclitaxel, and doxorubicin. [ABSTRACT FROM AUTHOR] more...

The utilization of enzymes for catalysis in organic solvents, while exhibiting selectivity to different substrates, is a big challenge. We report an amphiphilic random copolymer system that self‐assembles with enzymes in an organic solvent to form nanoreactors. These encapsulated enzymes are not denatured and they do preserve the catalytic activity. The cross‐linkable functional groups in the hydrophobic compartments of the polymers offer to control accessibility to the enzyme. This varied accessibility due to the polymer host, rather than the enzyme itself, endows the nanoreactor with an unnatural selectivity. The findings here highlight the significant potential of simple polymer‐based enzyme nanoreactors to execute selective organic reactions under non‐native conditions. [ABSTRACT FROM AUTHOR] more...

We report the synthesis and the micellar self‐assembly in aqueous media of novel amphiphilic block copolymers. The copolymers consist of a poly[(methyl methacrylate)‐co‐(hydroxypropyl methacrylate)] statistical copolymer block and a poly[oligo(ethylene glycol) methyl ether methacrylate] block, and were synthesized by reversible addition–fragmentation chain transfer polymerization. The amphiphilic P(MMA‐co‐HPMA)‐b‐POEGMA block copolymers contain monomers of differing polarity and in varying ratios. Furthermore, HPMA segments are chosen in order to enhance hydrogen bonding interactions within the core of spherical micelles formed by the copolymers in aqueous media, as evidenced by light scattering and fluorescence spectroscopy studies. The amphiphilic copolymers are able to encapsulate the hydrophobic drugs curcumin and indomethacin as found using light scattering and spectroscopic methods. © 2021 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR] more...

The self‐assembly behavior, in aqueous solution, of amphiphilic methacrylic random copolymers with perfluoroalkyl and polyoxyethylene side chains and the morphology of the resulting nanostructures are investigated by small‐angle neutron scattering (SANS). The results allow to clarify the effect of temperature on the self‐assembly features of copolymers and the structural morphology of both unimer single‐chain entities and larger multi‐chain aggregates of unimers. Shape, flexibility, and size of the aggregates are proved to be modulated by temperature and copolymer composition. The existence of three distinct phases of self‐assembled structures is pointed out as a function of increasing temperature: 1) globular unimers; 2) coexistence of extended unimers and aggregates; and 3) aggregates, which overall show full reversibility in a wide range of copolymer concentrations. [ABSTRACT FROM AUTHOR] more...

Poly(tert‐butyl acrylate) (PtBA) is a versatile hydrophobic macromolecule usually preferred in the development of new materials for a host of applications. PtBA homopolymers with well‐defined structure and controlled molecular weight in a wide range were successfully synthesized via radiation‐induced reversible addition–fragmentation chain transfer (RAFT) polymerization in the presence of a trithiocarbonate type RAFT agent. The polymerization of tBA was performed under 60Co γ‐irradiation in the presence of 2‐(dodecylthiocarbonothioylthio)‐2‐methylpropionic acid (DDMAT) as the RAFT agent in toluene at room temperature with three [tBA]/[DDMAT] ratios (400, 600 and 1000) and different irradiation times. Radiation‐induced polymerization of tBA displayed controlled free radical polymerization characteristics: a narrow molecular weight distribution (Mw/Mn ~ 1.1), pseudo first order kinetics and controlled molecular weights. The system followed the RAFT polymerization mechanism even at very low amounts of RAFT agent ([tBA]/[DDMAT] = 1000), and molecular weights up to 113 900 with narrow dispersity (Ð =1.06) were obtained. PtBA was further hydrolysed into different amphiphilic PtBA‐co‐poly(acrylic acid) (PAA) copolymers by low (27.5%) and high (77.3%) degrees of hydrolysis. The pH sensitivity of the two copolymers was investigated by dynamic light scattering at pH 2 and pH 9 (above and below the pKa value of PAA) and their hydrodynamic diameters and zeta potential values were determined. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR] more...

ABA and BAB triblock amphiphilic copolymers based on sucrose methacrylate and methyl methacrylate are synthesized by sequential reversible addition–fragmentation chain transfer polymerization using S,S′‐bis(R,R′‐dimethyl‐R′′‐acetic acid)‐trithiocarbonate as a chain transfer agent. The copolymers present narrow molar mass dispersity, controlled molar mass and architecture as determined by gel permeation chromatography and 1H and 13C nuclear magnetic resonance. The copolymers with molar and mass fractions of poly(sucrose methacrylate) block ranging from 1 to 22 mol% and 3 to 52 wt%, respectively, and different molar masses present characteristics of a surfactant such as self‐assembly. The self‐assembly of the triblock copolymers in water, N,N‐dimethylformamide (DMF), dichloromethane, tetrahydrofuran, or benzene results mostly in vesicles as confirmed by scanning electron microscopy images and small‐angle X‐ray of the dispersions. Moreover, the copolymers present the capability to stabilize aromatic molecules (Nile Red dye) and nonpolar solvents in an aqueous phase and polar ionic molecules (methylene blue) and water in a nonpolar medium, suggesting the potential for application in drug encapsulation, environmental remediation systems, and molecular extraction in liquid–liquid immiscible systems, for example. Films prepared by casting from copolymer solutions in DMF present a lamellar structure with the lamellar thickness varying according to the copolymer molar mass. [ABSTRACT FROM AUTHOR] more...

Biobased amphiphilic diblock copolymers are prepared thanks to the combination of reversible addition–fragmentation transfer (RAFT) polymerization and polymerization‐induced self‐assembly (PISA) in an eco‐friendly solvent mixture. First, the formation of a poly(acrylic acid) macroRAFT agent (PAA‐TTC) is performed in water at 70 °C. Then, in a series of experiments, the PAA‐TTC macroRAFT agent is used directly, without purification, as both chain transfer agent and stabilizing agent in the RAFT‐PISA of menthyl acrylate (MnA) in dispersion in an ethanol/water mixture. The polymerizations of MnA are fast with high final conversions and well‐controlled amphiphilic diblock copolymers are synthesized. Stable, sub‐micrometric spherical particles composed of the diblock copolymers are formed. The influence of the monomer concentration and the length of the solvophobic block on the diameter of the self‐assemblies is studied by means of dynamic light scattering and cryogenic transmission electron‐microscopy. [ABSTRACT FROM AUTHOR] more...

Conformity of two biological imaging entities, magnetic resonance imaging (MRI) and fluorescence imaging, is achieved through co‐assembly of a Gd(III)‐based metallosurfactant, conjugated polymeric nanoparticles, and amphiphilic block copolymer F127 (PEO106PPO70PEO106) followed by crosslinking with organosilica. The cross‐linked micelles with a size around 100 nm exhibit outstanding dispersion stability in aqueous and phosphate buffered saline solutions, bright fluorescence emission, and high relaxivities, providing a new approach to synthesize highly efficient bimodal contrast agents. The relaxivities of the co‐assembled micelles are synergistically enhanced by incorporation of Gd(III) complexes with high hydration number (q = 3) and elongation of rotation correlation time to achieve r1 values up to 105.37 mm−1 s−1 (at 1.5 T), which is over 20 times that of clinically used MRI contrast agents and among the highest values of all the nanoparticular MRI contrast agents. The external PEO layer endows these micelles with very low cytotoxicity for both in vitro and in vivo imaging. Meanwhile, thanks to the enhanced permeability and retention effect originating from their nanoscale sizes, the bimodal contrast agents show a prolonged blood circulation time in vivo and targeted accumulation at tumor regions to display outstanding MRI imaging performance. [ABSTRACT FROM AUTHOR] more...

Abstract: Well‐defined copolymers synthesized by combining poly(ethylene glycol) (PEG) and amino acid based building blocks are investigated with regard to their helical rigidity and self‐assembly. Optical active block copolymers reported here are designed to have a pendant amino acid and polymerizable group, that is, isonitrile in order to induce helix formation and reduce the mobility of polymer chains by forming a hydrogen bond network so that a helix with reasonable rigidity can be obtained. Due to the amphiphilicity and a relatively shorter PEG as a coil, these polymers form micelles as observed under transmission electron microscopy in which copolymers PEG108‐b‐PPIC764 and PEG108‐b‐PPIC1020 appear to be evolving into nanoparticles with a size distribution of 100–200 nm. Circular dichroism spectroscopy is employed to study the nature of the helix and its rigidity. The folding and unfolding of polymer helix as a result of the ability of a selective solvent to form/disrupt hydrogen bonds with the peptide linkage is also discussed to highlight the responsive nature of the polymer. [ABSTRACT FROM AUTHOR] more...

Supramolecular self-assembly of polymeric molecules for sharp-pH-sensitive (SPS) nanoparticles is an especially important application in biology. Here, amphiphilic polypeptide copolymers are synthesized and spontaneously assembled to micelles in aqueous solution, and protonation of the tertiary amine groups in the side-chain of the copolymer under weak acid causes the micelle disassembly, which is sharp-pH-sensitive, and the responsive pHs can be adjusted by adding salts. Size and morphologic change of the polymeric micelles are characterized by means of dynamic lighting scattering, transmission electron microscope (TEM), and atomic force microscope (AFM) in sequential pH alterations. It is found that the Hofmeister ions play a key factor in controlling the subtle interaction of different noncovalent bonds among polypeptide molecules during their self-assembly or disassembly. The physical property exploration of the SPS micelles may provide a new chance for the development of dynamic, complex nanostructures in various pH-responsive applications. [ABSTRACT FROM AUTHOR] more...

Small-molecule drugs often have limited solubility, display rapid clearance or poor selectivity that leads to undesired side-effects. Although prodrug strategies can improve solubility and lower toxicity, activation 'on demand' as well as targeted transport of prodrugs remains a challenge in drug delivery. Responsive polymeric nanoparticles can help meet these challenges with the encapsulation or conjugation of drugs, allowing release at the target site upon triggering by an internal or external stimulus. The adaptable design of polymeric nanoparticles allows them to play a vital role in achieving a specific and desired response following application of a specific stimulus. Here, the most recent progress in responsive polymeric nanoparticles is reviewed with a focus on the chemical properties of the utilized polymers. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR] more...

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] more...

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] more...

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] more...

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] more...

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] more...

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] more...

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] more...

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] more...

ABSTRACT Amphiphilic hyperbranched copolymer chains made of large hyperbranched poly(acrylic acid) cores grafted with short polystyrene stickers (HB-PAA n- g-PS n + 1) with different n values ( n = 1, 10, 47) were well prepared and confirmed by size exclusion chromatography, Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance. The study on the interchain association behavior of these amphiphilic chains indicates that larger HB-(PAA) n- g-(PS) n + 1 copolymer chains have a less tendency to undergo interchain association. Moreover, the simple vial-inversion and rheological experiments show that the apparent critical gel concentration ( Cg) decreases with n, but no sol-gel transition was observed for triblock PS-PAA-PS even when the concentration is up to 200 g L−1. Further transmission electron microscopy study of the latex particles prepared with HB-(PAA) n- g-(PS) n + 1 as surfactant reveals that the latex particles are spherical and narrowly dispersed; while the measured latex particle number ( Np) indicates the surfactant efficiency of HB-(PAA)47- g-(PS)48 is poorer than that of triblock PS-PAA-PS ( n = 1). Finally, pyrene solubilization measurement shows the solubilization efficiency of HB-(PAA) n- g-(PS) n + 1 copolymers decreases with n, consistent with the previous observed interchain association result. The present study demonstrates that both the chain topology and the styrene weight fraction dominates the final solution properties of amphiphilic HB-(PAA) n- g-(PS) n + 1 chains in aqueous solution. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 128-138 [ABSTRACT FROM AUTHOR] more...

ABSTRACT Copper-catalyzed azide-alkyne cycloaddition (CuAAC) was used to prepare glycosylated polyethylene (PE)-poly(ethylene glycol) (PEG) amphiphilic block copolymers. The synthetic approach involves preparation of alkyne-terminated PE- b-PEG followed by CuAAC reaction with different azide functionalized sugars. The alkyne-terminated PE- b-PEG was prepared by etherification reaction between hydroxyl-terminated PE- b-PEG ( Mn ∼ 875 g mol−1) and propargyl bromide and azidoethyl glycosides were prepared by glycosylation of 2-azidoethanol. Atmospheric pressure solids analysis probe-mass spectrometry was used as a novel solid state characterization tool to determine the outcome of the CuAAC click reaction and end-capping of PE- b-PEG by the azidoethyl glycoside group. The aqueous solution self-assembly behavior of these amphiphilic glycosylated polymers was explored by TEM and dye solubilization studies. Carbohydrate-bearing spherical aggregates with the ability to solubilize a hydrophobic dye were observed. The potential of these amphiphilic glycosylated polymers to self-assemble via electro-formation into giant carbohydrate-bearing polymersomes was also investigated using confocal fluorescence microscopy. An initial bioactivity study of the carbohydrate-bearing aggregates is furthermore presented. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5184-5193 [ABSTRACT FROM AUTHOR] more...

ABSTRACT An approach to the synthesis of new regular graft-copolymers polyimide (PI)- graft-polymethacrylic acid is elaborated, including (1) synthesis of multicenter PI macroinitiators, (2) controlled ATRP of tert-butylmethacrylate on the prepared macroinitiators, and (3) protonolysis of tert-butyl ester groups of side chains of the resulting PI- graft-poly( tert-butylmethacrylate). Experimental conditions for attaining complete conversions of the first and the third stages of the process are determined by means of 1H NMR and FTIR-spectroscopy. Polymer products of the first and the second stages of the process, as well as poly( tert-butylmethacrylate) side chains cleaved from the PI- graft-poly( tert-butylmethacrylate) copolymers by complete decomposition of the PI backbone under alkaline hydrolysis conditions, are characterized by GPC. The kinetics of poly( tert-butylmethacrylate) chain growth on a PI macroinitiator under ATRP conditions are studied. The results obtained provide evidence for the controlled character of the ATRP process and the regular structure of the synthesized graft-copolymers. It is shown that PI- g-PMAA PI brushes are significantly more efficient intracellular delivery agents for the potential photosensitizer [tetra(4-fluorophenyl)tetracyanoporhyrazine free base] than are the commonly used PEG-micelles. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4267-4281 [ABSTRACT FROM AUTHOR] more...

Long-subchain hyperbranched polystyrene (lsc-hp PSt) with uniform subchain length was obtained through copper-catalyzed azide-alkyne cycloaddition click chemistry from seesaw macromonomer of PSt having one alkynyl group anchored at the chain centre and two azido group attached to both chain ends [alkynyl-(PSt-N3)2]. After precipitation fraction, different portions of lsc-hp PSt having narrow overall molecular weight distribution were obtained for further grafting with alkynyl-capped poly( N-isopropylacrylamide) (alkynyl-PNIPAM), which was obtained via single-electron transfer living radical polymerization of NIPAM with propargyl 2-bromoisobutyrate as the initiator and grafted onto the peripheral azido groups of lsc-hp PSt via click chemistry. Thus, amphiphilic lsc-hp PSt grafted with PNIPAM chains (lsc-hp PSt- g-PNIPAM) was obtained and would have star-like conformation in tetrahydrofuran (THF). By replacing THF with water, lsc-hp PSt- g-PNIPAM was dissolved at molecular level in aqueous solution due to the hydrophilicity of PNIPAM and exhibited thermal induced shrinkage of PNIPAM arms. The water-insoluble lsc-hp PSt would collapse densely and could be served as a reservoir to absorb hydrophobic chemicals in aqueous solution. The influence of overall molecular weight of lsc-hp PSt on the absorption of pyrene was studied. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 [ABSTRACT FROM AUTHOR] more...

A series of carbazole-containing water-dispersible poly(acrylic acid)- b-(9-(4-vinylbenzyl)-9H-carbazole) block copolymers (poly(AA)- b-poly(VBK)) and water-soluble poly(methacrylic acid- ran-(9-(4-vinylbenzyl)-9H-carbazole)) (poly(MAA- ran-VBK)) random copolymers were synthesised in a controlled manner (i.e. low polydispersities $(\overline {M_{{\rm w}} } /\overline {M_{n} } < 1.3)$ by nitroxide-mediated polymerisation (NMP) using an SG1-based alkoxyamine initiator, BlocBuilder. Poly(AA)- b-poly(VBK) block copolymers were most easily accessed by using poly(AA) in its protected form as the macroinitiator for the 9-(4-vinylbenzyl)-9H-carbazole (VBK) block. Controlled polymerisation of MAA was accomplished using an excess of 10 mol.% SG1 relative to BlocBuilder with VBK as controlling co-monomer (initial molar feed content fVBK,0 = 0.03-0.20) in dimethylformamide at 80°C. Poly(MAA- ran-VBK) copolymers with a final VBK molar composition of FVBK < 0.30 resulted in water-soluble copolymers. In addition, as macroinitiators, poly(MAA- ran-VBK)s were sufficiently pseudo-living to reinitiate a second batch of monomer (90 mol.% methyl methacrylate with styrene) in organic solvent and by ab initio, surfactant-free emulsion polymerisation. In both cases, low polydispersity, amphiphilic block copolymers resulted $(\overline {M_{{\rm w}} } /\overline {M_{{\rm n}} } < 1.3)$. © 2012 Canadian Society for Chemical Engineering [ABSTRACT FROM AUTHOR] more...

In this paper, a straightforward method to produce poly(3-hydroxyalkanoate)-based multicompartment micelles (MCMs) is presented. Thiol-ene addition is used to graft sequentially perfluorooctyl chains and poly(ethylene glycol) oligomers onto poly(3-hydroxyoctanoate- co-hydroxyundecenoate) oligomers backbone. Well-defined copolymers are obtained as shown by 1H NMR and size-exclusion chromatography. After nanoprecipitation in water, novel PHA-based MCMs are evidenced by cryo-transmission electron microscopy. Moreover, the cytocompatibility of MCMs is demonstrated in vitro via cell viability assay. [ABSTRACT FROM AUTHOR] more...

Novel ABA type amphiphilic copolymers (PCL-APS-PCL) consisting of polycaprolactone (PCL) (A) as hydrophobic block and N, N′-bis (2-hydroxyethyl) methylamine ammonium propane sulfonate (APS) (B) as hydrophilic segment, self-assembled into nanoparticles (NPs) with solvent evaporation method. The sizes and size distributions of NPs were characterized by dynamic light scattering. The morphology of NPs was observed by scanning electron microscopy (SEM). The critical micelle concentration (CMC) was determined by fluorescent probe. The drug loading content (DLC) and the drug release amount were characterized by UV-visible spectrophotometer. The cytotoxicity of the NPs was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazoliumbromide (MTT) assay. It was found that the NPs were spherical in shape with sizes around 100 nm. The CMCs of the copolymers were quite low (×10−4 mg/mL). The DLC decreased with lengthening of hydrophobic PCL block. In vitro drug release experiment demonstrated that the release rate of paclitaxel sped with the decrease of PCL length. MTT results showed that NPs were nontoxic to osteoblast and human epithelial carcinoma (hela) cells. After drug loading, NPs could restrain the growth of hela or even kill hela cells. Therefore, these preliminary studies suggest that the novel PCL-APS-PCL NPs have a great potential application as anticancer drug-delivery carriers. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012. [ABSTRACT FROM AUTHOR] more...

Two chiral amphiphilic diblock copolymers with different relative lengths of the hydrophobic and hydrophilic blocks, poly(6‐O‐p‐vinylbenzyl‐1,2:3,4‐Di‐O‐isopropylidene‐D‐galactopyranose)‐b‐poly(N‐isopropylacrylamide) or poly(VBCPG)‐b‐poly(NIPAAM) and poly(20‐(hydroxymethyl)‐pregna‐1,4‐dien‐3‐one methacrylate)‐b‐poly(N‐isopropylacrylamide) or poly(MAC‐HPD)‐b‐poly(NIPAAM) were synthesized via consecutive reversible addition‐fragmentation chain‐transfer polymerizations of VBCPG or MAC‐HPD and NIPAAM. The chemical structures of these diblock copolymers were characterized by 1H nuclear magnetic resonance spectroscopy. These amphiphilic diblock copolymers could self‐assemble into micelles in aqueous solution, and the morphologies of micelles were investigated by transmission electron microscopy. By comparison with the lower critical solution temperatures (LCST) of poly(NIPAAM) homopolymer in deionized water (32 °C), a higher LCST of the chiral amphiphilic diblock copolymer (poly(VBCPG)‐b‐poly(NIPAAM)) was observed and the LCST increased with the relative length of the poly(VBCPG) block in the copolymer from 35 to 47 °C, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7690–7701, 2008 [ABSTRACT FROM AUTHOR] more...

Four‐arm star‐shaped poly[2‐(diethylamino)ethyl methacrylate]‐b‐poly[2‐hydroxyethyl methacrylate]s block copolymers using tetraphenylsilane (TPS) as a core with adjustable arm lengths are synthesized through two‐step atom transfer radical polymerizations. For comparison, a linear block copolymer with similar molecular weight is also prepared. The assembled star‐shaped copolymer micelles exhibit sizes of 102–139 nm and critical micelle concentrations of 1.49–3.93 mg L−1. Moreover, the bulky and rigid TPS core is advantageous for propping up the four star‐shaped arms to generate large intersegmental space. As a result, the drug‐loading capacity in the micelles is up to 33.97 wt%, much surpassing the linear counterpart (8.92 wt%) and the previously reported star‐shaped copolymers prepared using pentaerythritol as the core. Furthermore, the micelles show sensitive pH‐responsive drug release when the pH changes from 7.4 to 5.0. The in vitro cytotoxicity to Hela cells indicates that the doxorubicin (DOX)‐loaded micelles have similar anticancer activity to the pristine DOX. The combination of excellent micelle stability, high drug‐loading, sensitive pH response, and good anticancer activity endows the copolymers with promising application in drug control delivery for anticancer therapy. [ABSTRACT FROM AUTHOR] more...

The effect of UV irradiation on the cloud points (CP) of aqueous solutions of a random 1:1 copolymer of oligo(ethylene glycol) methyl ether methacrylate (OEGMA500) and a 2‐(hydroxyimino)aldehyde (HIA) functionalized methacrylate is presented. CPs are determined by visible spectroscopy and dynamic light scattering (DLS). 1H and 13C NMR experiments are carried out in D2O and DMSO‐d6 on the polymer and on an HIA‐functionalized model of the photoresponsive repeat unit. UV‐irradiated solutions exhibit an unprecedented increase of the phase‐separation temperature for an OEGMA photoresponsive copolymer (10–22 °C, depending on concentration and irradiation conditions). Phase separation is reversible with little hysteresis. With both pristine and irradiated polymer solutions, aggregate dimensions are <10 nm (DLS) at room temperature. Aggregates of >100 nm form at the CP and gradually grow as temperature increases, whereas the light‐induced processes of the repeat unit model in DMSO‐d6 are well identified (e.g., oxime E/Z isomerization and Norrish‐Yang cyclization of the aldehyde moiety), it is not straightforward to extrapolate such behavior to the polymeric solution in water. The remarkably large phototriggered thermal effect in the present work motivates further investigations on the solvent‐dependent photochemistry of HIA as a promising functional group for the synthesis of multi‐stimuli responsive materials. [ABSTRACT FROM AUTHOR] more...