Preparation and self‐assembly of poly(diglycidyl maleate‐co‐stearyl methacrylate)

Poly(diglycidyl maleate‐co‐stearyl methacrylate) (P(DGMA‐co‐SMA)) with reactive epoxy groups was synthesized by reaction of poly(maleic anhydride‐co‐stearyl methacrylate) (P(MA‐co‐SMA)) and epichlorohydrin. The effect of precipitant on self‐assembly behaviors of the resultant copolymer was investigated. It was found that vesicles and nanotubule liked aggregates can be obtained through self‐assembly of P(DGMA‐co‐SMA) in THF solution using CH₃CH₂OH (EtOH) as precipitant while spheral aggregates can be obtained using H₂O as precipitant. The mechanism of the self‐assembly behavior was discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Amphiphilic block copolymer poly(lactic acid)‐block‐(glycidylazide polymer)‐block‐polystyrene: synthesis and self‐assembly

The triblock energetic copolymer poly(lactic acid)‐block‐(glycidylazide polymer)‐block‐polystyrene (PLA‐b‐GAP‐b‐PS) was synthesized successfully through atom‐transfer radical polymerization (ATRP) of styrene and ring‐opening polymerization of d,l ‐lactide. The energetic macroinitiator GAP‐Br, which was made from reacting equimolar GAP with α‐bromoisobutyryl bromide, firstly triggered the ATRP of styrene with its bromide group, and then the hydroxyl group on the GAP end of the resulting diblock copolymer participated in the polymerization of lactide in the presence of stannous octoate. The triblock copolymer PLA‐b‐GAP‐b‐PS had a narrow distribution of molecular weight. In the copolymer, the PS block was solvophilic in toluene and improved the stability of the structure, the PLA block was solvophobic in toluene and served as the sacrificial component for the preparation of porous materials, and GAP was the basic and energetic material. The three blocks of the copolymer were fundamentally thermodynamically immiscible, which led to the self‐assembly of the block copolymer in solution. Further studies showed that the concentration and solubility of the copolymer and the polarity of the solvent affected the morphology and size of the micelles generated from the self‐assembly of PLA‐b‐GAP‐b‐PS. The micelles generated in organic solvents at 10 mg mL^?1 copolymer concentration were spherical but became irregular when water was used as a co‐solvent. The spherical micelles self‐assembled in toluene had three distinct layers, with the diameter of the micelles increasing from 60 to 250 nm as the concentration of the copolymer increased from 5 to 15 mg L^?1. © 2017 Society of Chemical Industry     

Synthesis,characterization, and self‐assembly of amphiphilic fluorinated gradient copolymer

An amphiphilic copolymer of acrylic acid (AA) and 2,2,2‐trifluoroethyl methacrylate (TFEMA) was synthesized by reversible addition‐fragmentation transfer (RAFT) copolymerization, using a feed method for adding TFEMA. The kinetics of the RAFT copolymerization agreed well with those characteristic of a first‐order reaction and the molecular weight of copolymers increased with the conversion increasing, both demonstrating that it proceeded in a controlled polymerization manner. Optimal copolymerization was achieved when the reaction was conducted at 70°C, using a molar ratio of TFEMA : AA : RAFT agent : initiator of 400 : 400 : 4 : 1. Analysis of instantaneous ¹H‐NMR results proved that the obtained copolymer had a chain structure with AA segments gradually changing to TFEMA segments. The copolymer films had lower surface free energies and slightly microphase separation structures. The amphiphilic copolymer with gradient structures could self‐assemble to form aggregates in selective solvents. The type and composition of solvent mixtures had great effects on the morphology and sizes of aggregates, which were investigated by transmission electron microscopy and dynamic light scattering, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013     

Synthesis and self‐assembly of amphiphilic star‐block copolymers consisting of polyethylene and poly(ethylene glycol) segments

We report on the synthesis and self‐assembly in water of well‐defined amphiphilic star‐block copolymers with a linear crystalline polyethylene (PE) segment and two or three poly(ethylene glycol) (PEG) segments as the building blocks. Initially, alkynyl‐terminated PE (PE‐?) is synthesized via esterification of pentynoic acid with hydroxyl‐terminated PE, which is prepared using chain shuttling ethylene polymerization with 2,6‐bis[1‐(2,6‐dimethylphenyl) imino ethyl] pyridine iron (II) dichloride/methylaluminoxane/diethyl zinc and subsequent in situ oxidation with oxygen. Then diazido‐ and triazido‐terminated PE (PE‐(N₃)₂ and PE‐(N₃)₃) are obtained by the click reactions between PE‐? and coupling agents containing triazido or tetraazido, respectively. Finally, the three‐arm and four‐arm star‐block copolymers, PE‐b‐(PEG)₂ and PE‐b‐(PEG)₃, are prepared by click reactions between PE‐(N₃)₂ or PE‐(N₃)₃ and alkynyl‐terminated PEG. The self‐assembly of the resultant amphiphilic star‐block copolymers in water was investigated by dynamic light scattering, transmission electron microscopy, and atomic force microscopy. It is found that, in water, a solvent selectively good for PEG blocks; these star‐block copolymer chains could self‐assemble to form platelet‐like micelles with insoluble PE blocks as crystalline core and soluble PEG blocks as shell. The confined crystallization of PE blocks in self‐assembled structure formed in aqueous solution is investigated by differential scanning calorimetry. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Growth control and long‐range self‐assembly of poly(methyl methacrylate) nanospheres

A systematic investigation of the reaction time and role of a cosolvent (toluene) in inducing several beneficial effects on nanobead properties was performed to achieve the synthesis of poly(methyl methacrylate) nanospheres. In particular, good dimensional control in the range of 100–400 nm, very low polydispersity, and a spherical shape were consistently obtained. Different parameters affecting the self‐assembly mechanism leading to the deposition of hard‐sphere photonic crystals were studied, and the features underlying their role were examined. Photonic crystals were produced by the evaporation of nanosphere suspensions at different temperatures, relative humidities, and suspension ionic strengths and with different substrate materials. The proper conditions for obtaining large crystal domains were determined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4493–4499, 2006     

Cationic amphiphilic copolymers: synthesis,characterization, self‐assembly and drug‐loading capacity

Amphiphilic copolymers with cationic hydrophilic moieties and different ratios of hydrophobic portion to hydrophilic portion were designed and synthesized via the combination of hydrosilylation reactions and quaternization reactions. The structures were characterized through Fourier transform infrared spectroscopy, ¹H NMR , ¹³C NMR and gel permeation chromatography. The measurements of critical micelle concentrations, electrical conductivities and zeta potentials indicated that the copolymers could self‐assemble into nanoparticles with charges around the surface in aqueous solution. The sizes of the micelles were between 67 nm and 104 nm detected by dynamic light scattering. The self‐assembled micelles were used as drug carriers to encapsulate a model drug (tocopherol), and their drug‐loading content (DLC ) and efficiency (DLE ) were determined by UV ?visible spectra, resulting in considerable drug‐loading capacity to a tocopherol maximum up to 17.2% (DLC ) and 80.3% (DLE ) with a size of 90 nm. The blank micelles and drug‐loaded micelles displayed a spherical shape detected by transmission electron microscopy, which demonstrated not only the self‐assembly behaviors but also the drug‐loading performances of the cationic amphiphilic copolymers. All the results demonstrated that the cationic amphiphilic copolymers could be used as potential electric‐responsive drug carriers. © 2017 Society of Chemical Industry     

Vesicular and micellar self‐assembly of stimuli‐responsive poly(N‐isopropyl acrylamide‐b‐9‐anthracene methyl methacrylate) amphiphilic diblock copolymers

Dually responsive amphiphilic diblock copolymers consisting of hydrophilic poly(N‐isopropyl acrylamide) [poly(NIPAAm)] and hydrophobic poly(9‐anthracene methyl methacrylate) were synthesized by reversible addition fragmentation chain‐transfer (RAFT) polymerization with 3‐(benzyl sulfanyl thiocarbonyl sulfanyl) propionic acid as a chain‐transfer agent. In the first step, the poly(NIPAAm) chain was grown to make a macro‐RAFT agent, and in the second step, the chain was extended by hydrophobic 9‐anthryl methyl methacrylate to yield amphiphilic poly(N‐isopropyl acrylamide‐b‐9‐anthracene methyl methacrylate) block copolymers. The formation of copolymers with three different hydrophobic block lengths and a fixed hydrophilic block was confirmed from their molecular weights. The self‐assembly of these copolymers was studied through the determination of the lower critical solution temperature and critical micelle concentration of the copolymers in aqueous solution. The self‐assembled block copolymers displayed vesicular morphology in the case of the small hydrophobic chain, but the morphology gradually turned into a micellar type when the hydrophobic chain length was increased. The variations in the length and chemical composition of the blocks allowed the tuning of the block copolymer responsiveness toward both the pH and temperature. The resulting self‐assembled structures underwent thermally induced and pH‐induced morphological transitions from vesicles to micelles and vice versa in aqueous solution. These dually responsive amphiphilic diblock copolymers have potential applications in the encapsulation of both hydrophobic and hydrophilic drug molecules, as evidenced from the dye encapsulation studies. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46474.     

Self‐assembled poly(styrene‐co‐N‐isopropylacrylamide) film induced by capillary force

The monodisperse poly(styrene‐co‐N‐isopropylacrylamide) (poly(St‐co‐NIPAAm)) particles prepared by emulsifier‐free emulsion polymerization with microwave irradiation were induced by capillary forces to self‐assemble, and formed the two‐dimensional films on the clean glassware wafer substrates. The morphologies of the two‐dimensional films were characterized by scanning electron microscopy (SEM) and atom force microscopy (AFM). The results showed that monodisperse poly(St‐co‐NIPAAm) particles could form ordered two‐dimensional films by capillary forces. With NIPAAm concentration increasing, there gradually appeared surface undulations or surface defective region on the two‐dimensional films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3514–3519, 2006     

Towards enhanced electrochemical capacitance with self‐assembled synthesis of poly(pyrrole‐co‐o‐toluidine) nanoparticles

Poly(pyrrole‐co‐o‐toluidine) (PPOT) nanoparticles for electrochemical capacitors are easily and productively synthesized by a chemical oxidative polymerization of pyrrole (PY) and o‐toluidine (OT) in 0.5M HCl without any external additive. The polymerization yield, electrical conductivity, and size of the copolymer nanoparticles can significantly be optimized by the oxidant/monomer molar ratio and polymerization temperature. The chemical structure of the obtained copolymer is characterized by UV–vis and FTIR. The copolymer nanoparticles synthesized at 10°C are found to generally have irregular granular morphology with a diameter of 60–100 nm and a small polydispersity index of 1.06 by laser particle‐size analyzer, FE‐SEM, and TEM, and good dispersibility in water. The formation mechanism of the nanoparticles is proposed based on the powerful amphipathicity from comonomer aggregate formed by PY and OT in the monomer solution. The PPOT nanoparticles possess a specific capacitance of 310 F g^?1 at 25 mV s^?1 as well as retain 81% of the initial specific capacitance value after 1000 cycles, while its energy density and power density are found to be 40.2 and 1196 W Kg^?1 at 2 A g^?1. The enhanced electrochemical properties can be attributed to the nanostructural advantage of the PPOT. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42995.     

Self‐assembly of bovine serum albumin and poly(acrylic acid) induced by noncovalent bonds

Bovine serum albumin/poly(acrylic acid), BSA/PAA, nano‐scaled particles were produced by noncovalent bonds induced self‐assembly method at acid pH area. Proper conditions during preparation process, such as pH value, BSA/PAA weight ratio(WR), PAA molecular weight, were researched by studying the hydrodynamic diameter, polydispersity index, and ζ potential of the nanoparticles. Complex formation between BSA and PAA was studied by FT‐IR, AFM, and TEM. BSA chains are supposed to be partly trapped in the nanoparticles core after interaction with PAA because of the electrostatic attractions and hydrogen bonds interactions between BSA and PAA, while the rest of the BSA chains should form the shell of the nanoparticles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Alternative procedure for the incorporation of quantum dots into poly(N‐isopropyl acrylamide‐co‐acrylic acid) microgels based on multiple interactions

Monodisperse fluorescent poly(N‐isopropyl acrylamide‐co‐acrylic acid) microgels doped with quantum dots (QDs) were fabricated as follows. First, cysteamine‐capped cadmium telluride (CA–CdTe) QDs were introduced into the microgels at pH 7 by electrostatic interactions. Afterward, the CA–CdTe QDs were further immobilized in the microgels by the collapse of the polymer network when the pH of solution was adjusted to 4. In this system, there existed multiple interactions between the CA–CdTe QDs and the microgels, including hydrogen bonds, electrostatic interactions, and coordination bonds. The photoluminescence intensity and maximum emission wavelength of the resulting microgels could be easily adjusted by changes in the content of the CA–CdTe QDs in the hybrid microgels (HMs) and with differently sized QDs, respectively. We found that the lower the addition of CA–CdTe QDs was, the bigger the blueshift of the photoluminescence spectra of the HMs was and the weaker the photoluminescence intensity was. Finally, temperature‐responsive emission of the HMs was examined. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43227.     

Synthesis and physicochemical characterization of amphiphilic block copolymer self‐aggregates formed by poly(ethylene glycol)‐block‐poly(ϵ‐caprolactone)

Diblock copolymers with different poly(ε‐caprolactone) (PCL) block lengths were synthesized by ring‐opening polymerization of ε‐caprolactone in the presence of monomethoxy poly(ethylene glycol) (mPEG‐OH, MW 2000) as initiator. The self‐aggregation behaviors and microscopic characteristics of the diblock copolymer self‐aggregates, prepared by the diafiltration method, were investigated by using ¹H NMR, dynamic light scattering (DLS), and fluorescence spectroscopy. The PEG–PCL block copolymers formed the self‐aggregate in an aqueous environment by intra‐ and/or intermolecular association between hydrophobic PCL chains. The critical aggregation concentrations of the block copolymer self‐aggregate became lower with increasing hydrophobic PCL block length. On the other hand, reverse trends of mean hydrodynamic diameters were measured by DLS owing to the increasing bulkiness of the hydrophobic chains and hydrophobic interaction between the PCL microdomains. The partition equilibrium constants (K_v) of pyrene, measured by fluorescence spectroscopy, revealed that the inner core hydrophobicity of the nanoparticles increased with increasing PCL chain length. The aggregation number of PCL chain per one hydrophobic microdomain, investigated by the fluorescence quenching method using cetylpyridinium chloride as a quencher, revealed that 4–20 block copolymer chains were needed to form a hydrophobic microdomain, depending on PCL block length. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3520–3527, 2006     

Interpolymer‐specific interactions and miscibility in poly(styrene‐co‐acrylic acid)/poly(styrene‐co‐N,N‐dimethylacrylamide) blends

The miscibility or complexation of poly(styrene‐co‐acrylic acid) containing 27 mol % of acrylic acid (SAA‐27) and poly(styrene‐co‐N,N‐dimethylacrylamide) containing 17 or 32 mol % of N,N‐dimethylacrylamide (SAD‐17, SAD‐32) or poly(N,N‐dimethylacrylamide) (PDMA) were investigated by different techniques. The differential scanning calorimetry (DSC) analysis showed that a single glass‐transition temperature was observed for all the mixtures prepared from tetrahydrofuran (THF) or butan‐2‐one. This is an evidence of their miscibility or complexation over the entire composition range. As the content of the basic constituent increases as within SAA‐27/SAD‐32 and SAA‐27/PDMA, higher number of specific interpolymer interactins occurred and led to the formation of interpolymer complexes in butan‐2‐one. The qualitative Fourier transform infrared (FTIR) spectroscopy study carried out for SAA‐27/SAD‐17 blends revealed that hydrogen bonding occurred between the hydroxyl groups of SAA‐27 and the carbonyl amide of SAD‐17. Quantitative analysis carried out in the 160–210°C temperature range for the SAA‐27 copolymer and its blends of different ratios using the Painter–Coleman association model led to the estimation of the equilibrium constants K₂, K_A and the enthalpies of hydrogen bond formation. These blends are miscible even at 180°C as confirmed from the negative values of the total free energy of mixing ΔG_M over the entire blend composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1011–1024, 2007     

Controllable self‐assembly of polystyrene‐block‐poly(2‐vinylpyridine)

Block copolymers can form various ordered structures by self‐assembly, and their composites with inorganic materials may give surprising properties. This review summarizes recent developments in the preparation, mechanism and application of various types of self‐assembly of polystyrene‐block‐poly(2‐vinylpyridine) (PS‐b‐P2VP). The focus of the review is on how to control the self‐assembly of the dynamic and ordered structure of PS‐b‐P2VP based materials by applying effective factors such as thermal annealing, solvent annealing, block composition and blending. Moreover, the combination of the self‐assembly of PS‐b‐P2VP and various nanoparticles, with potentials in drug delivery, sensors and catalysis, is highlighted. © 2018 Society of Chemical Industry     

Emulsifier‐free reversible addition–fragmentation chain transfer emulsion polymerization of alkyl acrylates mediated by symmetrical trithiocarbonates based on poly(acrylic acid)

Emulsifier‐free batch emulsion polymerization of n‐butyl acrylate and its semi‐batch copolymerization with 2,2,3,3,4,4,5,5‐octafluoropentyl acrylate and 2,2,3,4,4,4‐hexafluorobutyl acrylate both mediated by poly(acrylic acid) containing the trithiocarbonate group in the chain was employed to produce amphiphilic triblock copolymers. The polymerization‐induced self‐assembly of these copolymers in aqueous media gave rise to spherical core–shell particles. Irrespective of the experimental conditions, the polymeric product was characterized by a bimodal molecular weight distribution. The apparent violation of the reversible addition–fragmentation chain transfer polymerization mechanism may be attributed to restricted accessibility of the trithiocarbonate group in the self‐assembled block copolymers for propagating radicals that enter into the particle. Mean‐field theoretical arguments were employed to explain the exclusively spherical morphology of the particles observed in the experiment. © 2019 Society of Chemical Industry     

Microporous polypropylene fibers containing fine particles of poly(styrene‐co‐divinylbenzene) or poly(glycidylmethacrylate‐co‐divinylbenzene)

Styrene‐divinylbenzene or glycidylmethacrylate‐divinyl‐benzene were copolymerized in powdery polypropylene suspended in water and the resultant polymer composites were blended with a definite amount of polypropylene. The products consisted of polypropylene and the fine particles of the copolymer, which were uniformly dispersed in polypropylene phase. These products were melt‐spun to prepare polypropylene fibers containing the fine particles and then the fibers were stretched to make the fibers microporous. Some properties were estimated: porosity, 1.6–19.7%; average pore size, 0.004–0.009 µm; and specific surface, 9–137 m²/g. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 722–727, 1999     

Water‐dispersible porous polyisoprene‐block‐poly(acrylic acid) microspheres

Two polyisoprene‐block‐poly(tert‐butyl acrylate) (PI‐b‐PtBA) samples and a poly(tert‐butyl acrylate) (PtBA) homopolymer (hPtBA) were prepared by anionic polymerization and characterized by light scattering, size exclusion chromatography, and NMR. The tert‐butyl groups were removed from one of the diblocks to yield amphiphilic polyisoprene‐block‐poly(acrylic acid) (PI‐b‐PAA). PI‐b‐PAA was then used as the surfactant to disperse dichloromethane containing PI‐b‐PtBA and hPtBA at different weight ratios as oil droplets in water. Solid microspheres containing segregated polyisoprene (PI) and PtBA/hPtBA domains were obtained after dichloromethane evaporation. Permanent microspheres were obtained after PI domain crosslinking with sulfur monochloride. Porous microspheres were produced after the hydrolysis of PtBA and the extraction of the homopoly(acrylic acid) chains. The shape and connectivity of the poly(acrylic acid)‐lined pores were tuned by changes in the PtBA/hPtBA content in the precursor microspheres. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2785–2793, 2003     

Amphiphilic styrene–acrylic acid copolymers from the free‐radical retrograde‐precipitation polymerization (FRRPP) process

The free‐radical retrograde‐precipitation polymerization (or FRRPP) process, a free‐radical polymerization that occurs above the lower critical solution temperature (LCST), was extended to copolymer formation. Control over the rate of polymerization and entrapment of polymer radicals in the FRRPP process was used to generate tapered styrene–acrylic acid block copolymers. To show the effectiveness of the FRRPP process, the same procedure was used with solvents that are not LCST‐based precipitants for the polymer. Kinetic data show substantial chain termination in non‐FRRPP copolymerization systems. Molecular weight information also shows propagation control in the FRRPP system. Solubilization and emulsification studies also indicate the capability of the FRRPP system in generating a much higher proportion of amphiphilic tapered block copolymers in the solid product. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 426–431, 2003     

Hydrogen bond‐mediated self‐assembly and supramolecular structures of diblock copolymer mixtures

This review summarizes recent advances in the preparation of hydrogen bonding block copolymer mixtures and the supramolecular structures they form through multiple hydrogen bonding interactions. Hydrogen bonding in block copolymer mixtures that form nanostructures and have unusual electronic, photonic and magnetic properties is a topic of great interest in polymer science. Combining the self‐assembly of block copolymers with supramolecular structures offers unique possibilities to create new materials with tunable and responsive properties. The self‐assembly of structures from diblock copolymer mixtures in the bulk state is readily controlled by varying the weight fraction of the block copolymer mixture and the copolymer composition; in solution, the morphologies are dependent on the copolymer composition, the copolymer concentration, the nature of the common solvent, the amount of the selective solvent and, most importantly, the hydrogen bonding strength. Copyright © 2008 Society of Chemical Industry     

Construct biomimetic giant vesicles via self‐assembly of poly(2‐methacryloyloxyethyl phosphorylcholine)‐block‐poly(D,L‐lactide)

The poly(2‐methacryloyloxyethyl phosphorylcholine)‐block‐poly(D ,L ‐lactide) (PMPC‐b‐PLA) was specially designed to develop biomimetic giant vesicles (GVs) and giant large compound vesicles via a simple spontaneous assemble in aqueous solution. The weight fraction of the hydrophilic PMPC block (f_PC) was proved to play an important role in the size and morphology control of the self‐assembled aggregates. The GVs with controlled micrometer size and biomimetic PMPC corona have great potential as artificial cell models. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010