Particle and breath figure formation of triblock copolymers having self‐complementary hydrogen‐bonding units

Novel triblock copolymers having self‐complementary hydrogen‐bonding units were synthesized by using reversible addition–fragmentation transfer polymerization. As characterized by dynamic light scattering and atomic force microscopy, these polymers formed noncovalently crosslinked polymer particles and showed an aggregation behavior by intermolecular and intramolecular interactions. At low concentration, polymers formed nanoparticles, and the particle diameter increased with increasing polymer concentration. Well‐ordered hexagonal microstructures were prepared by “Breath Figure” technique with the triblock copolymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and characterization of negative‐type photosensitive hyperbranched polyimides with excellent organosolubility from an A2 + B3 monomer system

A series of photosensitive hyperbranched polyimides (HB‐PIs) were prepared through facile end‐group modifications of the fully imidized polymer. A triamine, 1,3,5‐tris(4‐aminophenoxy)benzene, and a dianhydride, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, were condensed with a dropwise addition method in a molar ratio of 1/2 to afford an anhydride‐terminated poly(amic acid) precursor, which was then end‐capped by 4‐aminophenol and chemically imidized to yield a phenol‐terminated HB‐PI. The modifications of the terminal phenol groups of the polyimide by acyl chloride compounds (acryloyl chloride, methylacryloyl chloride, and cinnamoyl chloride) gave the target polymers. The photosensitive HB‐PIs showed good thermal properties and excellent solubility even in low‐boiling‐point solvents at room temperature, such as acetone, 1,1,2‐trichloroethane, tetrahydrofuran, and chloroform. Photosensitive property studies revealed good photolithographic properties with a resolution greater than 3 μm and a sensitivity of 650–680 mJ/cm². © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1735–1744, 2004     

Synthesis,characterization, and electroluminescence properties of poly(fluorenevinylene benzobisthiazoles)

A series of vinylene‐linked copolymers based on electron‐deficient benzobisthiazole and electron‐rich fluorene moieties were synthesized via Horner–Wadsworth–Emmons polymerization. Three different polymers P1 , P2 , and P3 , were prepared bearing octyl, 3,7‐dimethyloctyl, and 2‐(2‐ethoxy)ethoxyethyl side chains, respectively. The polymers all possessed moderate molecular weights, good solubility in aprotic organic solvents, and high fluorescence quantum efficiencies in dilute solutions. P2 , which bore branched 3,7‐dimethyloctyl side chains, exhibited better solubility than the other polymers, but also exhibited the lowest thermal decomposition temperature of all polymers. Overall, the impact of the side chains on the polymers optical properties in solution was negligible as all three polymers gave similar absorption and emission spectra in both solution and film. Guest‐host light‐emitting diodes using dilute blends of the polymers in a poly(N‐vinylcarbazole) host gave blue‐green emission with P2 exhibiting the highest luminous efficiency, 0.61 Cd/A at ～500 nm. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Surface covalent encapsulation of multiwalled carbon nanotubes with poly(acryloyl chloride) grafted poly(ethylene glycol)

Multiwall carbon nanotube (MWNT) was grafted with polyacrylate‐g‐poly (ethylene glycol) via the following two steps. First, hydroxyl groups on the surface of acid‐treated MWNT reacted with linear poly(acryloyl chloride) to generate graft on MWNT; secondly, the remaining acryloyl chloride groups were subjected to esterification with poly(ethylene glycol) leading the grafted chains on the surface of MWNTs. Thus obtained grafted MWNT was characterized using Fourier transform infrared spectrometer, transmission electron microscopy, and X‐ray photoelectron spectroscopy. Thermogravimetric analysis showed that the weight fraction of grafted polymers amounted to 80% of the modified MWNT. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6880–6887, 2006     

Polyaniline copolymers with solvent‐mimic side chains

We investigated new polyaniline copolymers with solvent‐mimic side chains for enhanced processability in various solvents. The solvent‐mimic side chains, benzyloxypropoxy (BOP), phenoxybutoxy (POB), and dihydroxypropoxy (DHP), were introduced into copolymers and used with nonpolar aromatic and polar alcoholic solvents, respectively. Compared to a polyaniline homopolymer, polyaniline copolymers with a small amount of side chains (<4 mol %) exhibit different physical properties, including film‐forming ability. This can be attributed to the solvent‐mimic side chains strongly interacting with the solvent and/or the polyaniline backbone. Especially, in nonpolar aromatic solvents, polyaniline copolymers with nonpolar aromatic BOP and POB side chains exhibit good film‐forming ability leading to high electrical conductivity, while the polyaniline homopolymer did not form a film. Therefore, introducing solvent‐mimic side chains in conducting polymers is a very attractive method of enhancing their processability and physical properties. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1986–1995     

Synthesis of high‐order multiblock core cross‐linked star polymers

Core cross‐linked star (CCS) polymers with radiating arms composed of high‐order multiblock copolymers have been synthesized in a one‐pot system via iterative copper‐mediated radical polymerization. The employed “arm‐first” technique ensures the multiblock sequence of the macroinitiator is carried through to the star structure with no arm defects. The versatility of this approach is demonstrated by the synthesis of three distinct star polymers with differing arm compositions, two with an alternating ABABAB block sequence and one with six different block units (i.e. ABCDEF). Owing to the star architecture, CCS polymers in which the arm composition consists of alternating hydrophilic–hydrophobic (ABABAB) segments undergo supramolecular self‐assembly in selective solvents, whereas linear polymers with the same block sequence did not yield self‐assembled structures, as evidenced by DLS analysis. The combination of microstructural and topological control in CCS polymers offers exciting possibilities for the development of tailor‐made nanoparticles with spatially defined regions of functionality. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 135–143     

Synthesis and characterization of biodegradable poly(ester anhydride) based on ε‐caprolactone and adipic anhydride initiated by potassium poly(ethylene glycol)ate

Novel biodegradable poly(ester anhydride) block copolymers based on ε‐caprolactone (ε‐CL) and adipic anhydride (AA) were prepared by sequential polymerization. ε‐CL was first initiated by potassium poly(ethylene glycol)ate and polymerized into active chains (PCL‐O^?K⁺), which were then used to initiate the ring‐opening polymerization of AA. The effects of the AA feed ratio, solvent polarity, monomer concentration, and temperature on sequential polymerization were investigated. The copolymers, obtained under different conditions, were characterized by Fourier transform infrared, ¹H NMR, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). The GPC results showed that the weight‐average molecular weights of the block copolymers were approximately 6.0 × 10⁴. The DSC results indicated the immiscibility of the two components. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1511–1520, 2003     

Synthesis and self‐assembly of helical polypeptide‐random coil amphiphilic diblock copolymer

Three amphiphilic rod‐coil diblock copolymers, poly(2‐ethyl‐2‐oxazoline‐b‐γ‐benzyl‐L ‐glutamate) (PEOz‐b‐PBLG), incorporating the same‐length PEOz block length and various lengths of their PBLG blocks, were synthesized through a combining of living cationic and N‐carboxyanhydride (NCA) ring‐opening polymerizations. In the bulk, these block copolymers display thermotropic liquid crystalline behavior. The self‐assembled aggregates that formed from these diblock copolymers in aqueous solution exhibited morphologies that differed from those obtained in α‐helicogenic solvents, that is, solvents in which the PBLG blocks adopt rigid α‐helix conformations. In aqueous solution, the block copolymers self‐assembled into spherical micelles and vesicular aggregates because of their amphiphilic structures. In helicogenic solvents (in this case, toluene and benzyl alcohol), the PEOz‐b‐PBLG copolymers exhibited rod‐coil chain properties, which result in a diverse array of aggregate morphologies (spheres, vesicles, ribbons, and tube nanostructures) and thermoreversible gelation behavior. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3108–3119, 2008     

Synthesis and Hierarchical Self‐Assembly of Diphenylalanine‐Based Homopolymer and Copolymers By RAFT Polymerization

Dipeptide diphenylalanine has attracted significant research interests because of its ability to self‐assemble into various nanostructures such as nanotubes, nanowires, and nanoribbons. In this article, we present the synthesis and self‐assembly of a novel diphenylalanine‐based homopolymer and block/random copolymers by the reversible addition–fragmentation chain transfer (RAFT) polymerization of an acrylamide having a dipeptide moiety. The RAFT polymerization of N‐acryloyl‐l ,l ‐diphenylalanine (A‐Phe‐Phe‐OH) afforded novel amino acid‐based polymers with predetermined molecular weights and relatively narrow‐molecular weight distributions. The hierarchical self‐assembled structures of poly(A‐Phe‐Phe‐OH), which involve nanorods, larger nanofiber‐like microcrystals, and fiber bundles, were characterized by atomic force microscopy (AFM), transmission electron microscopy, scanning electron microscopy, and dynamic light scattering measurements. The circular dichroic measurements of poly(A‐Phe‐Phe‐OH) revealed its characteristic chiroptical property, which is affected by the nature of the solvents and the addition of urea and salts via hydrophobic, hydrogen bonding, and electrostatic interactions. Thermo‐ and pH‐responsive block and random copolymers composed of A‐Phe‐Phe‐OH and N‐isopropylacrylamide were synthesized by RAFT polymerization, and the thermoresponsive properties and assembled structures of the resulting copolymers were investigated by AFM and turbidity measurements. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2562–2574     

Novel thermally latent self‐crosslinkable copolymers bearing oxetane and hemiacetal ester moieties: The synthesis,self‐crosslinking behavior,and thermal properties

Novel thermally latent self‐crosslinkable copolymers ( 14 and 15 ) containing hemiacetal ester and oxetane moieties were synthesized by the radical copolymerizations of 1‐propoxyethyl methacrylate, 3‐ethyl‐3‐methacryloyloxymethyl oxetane, and/or n‐butyl methacrylate at 60 °C in the presence of 2,2′‐azoisobutylonitrile as an initiator. The obtained copolymers showed good solubility for common organic solvents such as tetrahydrofuran, chloroform, and dimethyl sulfoxide (DMSO). The thermal crosslinking behaviors were examined with several Lewis acid catalysts ( 6 ). In particular, the treatment with aluminum‐2‐ethylhexanate triethanolamine complex ( 6c ) at 160 °C was found to efficiently yield the corresponding self‐crosslinked polymers ( 14′ and 15′ ). Incidentally, the resulting products were hardly insoluble in various organic solvents, including DMSO. The thermal properties of the obtained self‐crosslinked polymers 14′ and 15′ were estimated by thermogravimetric analysis and differential scanning calorimetry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4260–4270, 2005     

Synthesis of dendronized polymer brushes containing metallo‐supramolecular polymer side chains

A new kind of dendronized polymer brush with metallo‐supramolecular polymer side chains was fabricated by a combination of macromonomer and graft‐to approach. The alternating copolymers of maleic anhydride and styryl macromonomers pendant with Fréchet‐type dendrons of three generations were reported previously. In this article, terpyridine groups were introduced along the backbone of the dendronized polymers through the amidolysis of anhydride groups. The terpyridine functionalized PEO linear chains were then incorporated through the complexation of terpyridine and Ru(II) ion. Thus, dendronized polymer brushes with amphiphilic properties were synthesized. AFM analysis showed worm‐like single molecular morphologies of the polymers of three generations, and ¹H NMR analysis indicated that such molecular brushes had an amphiphilic nature in solution. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3303–3310, 2007     

Hybrid amphiphilic block copolymers containing polyhedral oligomeric silsesquioxane: Synthesis,characterization, and self‐assembly in solutions

In this article, the amphiphilic block copolymers containing polyhedral oligomeric silsesquioxane (POSS), namely PMAPOSS‐b‐PAA and PMAPOSS‐b‐P(AA‐co‐St), were synthesized consecutively by reversible addition–fragmentation chain transfer and selective hydrolysis, and characterized by ¹H NMR, ¹³C NMR, Fourier transform infrared spectroscopy and gel permeation chromatography. In the presence of the nearly gradient styrene distribution along the hydrophilic block with a feed molar ratio of tert‐butyl acrylate (tBA) to St being 10/1, patterned core‐corona nanoparticles (NPs) were formed from the mixture of good/selective solvents (THF/water) by a simple evaporation process at room temperature. With the extending of the co‐block length, the self‐assembled NPs exhibited phase separation behavior of spheres‐dispersed, onion‐like and onion‐cluster hierarchical structures in turn. However, while a change in the feed molar ratio occurred, it resulted in the formation of typical core‐shell micelles (20/1, tBA/St) and disordered particles (5/1, tBA/St), respectively. Furthermore, the self‐assembly behavior of PMAPOSS‐b‐P(AA‐co‐St) in DMF was investigated, which showed that it could perform a mixture morphology of well‐dispersive sphere micelles and large aggregate of micelles. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and properties of novel functional polymers from tetrachlorinated perylene bisimide

Asymmetric tetrachlorinated perylene‐3,4,9,10‐tetracarboxylic acid bisimides (4Cl‐PBI) were prepared in one‐pot by a reaction of tetrachlorinated perylene‐3,4,9,10‐tetracarboxylic acid dianhydride with a mixture of 2‐aminoethanol and dodecanamine or 2‐decyltetradecan‐1‐amine. Then, two 4Cl‐PBI methacrylates bearing one (M1) and two (M2) long alkyl tails were prepared, and a series of functional homopolymers were obtained by subjecting conventional radical polymerization and atom transfer radical polymerization. Furthermore, amphiphilic block copolymers pendent with 4Cl‐PBI units, PEO‐PM1 and PEO‐PM2, were prepared using monomethoxyl PEO bromoisobutyrate as a macroinitiator. Size exclusion chromatography, UV–vis spectroscopy, fluorescence spectroscopy, and cyclic voltammetry have been applied to characterize the polymers obtained. Moreover, the Ullmann reactions between the grafted 4Cl‐PBI units were conducted to form large π units, and the PEO‐PM2 block copolymers gave di‐ or tri‐PBI units in about 30%. Also, self‐assembly of the amphiphilic block copolymers PEO‐PM1 and PEO‐PM2 in water was applied to generate spherical nanoparticles of 4Cl‐PBI. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and self‐assembly of diblock copolymers bearing 2‐nitrobenzyl photocleavable side groups

The light‐responsive behavior in solution and in thin films of block copolymers bearing 2‐nitrobenzyl photocleavable esters as side groups is discussed in this article. The polymers were synthesized by grafting 2‐nitrobenzyl moieties onto poly(acrylic acid)‐block‐polystyrene (PAA‐b‐PS) precursor polymers, leading to poly(2‐nitrobenzyl acrylate‐random‐acrylic acid)‐block‐polystyrene (P(NBA‐r‐AA)‐b‐PS) block copolymers. The UV irradiation of the block copolymers in a selective solvent for PS led to the formation of micelles that were used to trap hydrophilic molecules inside their core (light‐induced encapsulation). In addition, thin films consisting of light‐responsive P(NBA‐r‐AA) cylinders surrounded by a PS matrix were achieved by the self‐assembly of P(NBA‐r‐AA)‐b‐PS copolymers onto silicon substrates. Exposing these films to UV irradiation generates nanostructured materials containing carboxylic acids inside the cylindrical nanodomains. The availability of these chemical functions was demonstrated by reacting them with a functional fluorescent dye. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Poly(perylene‐alt‐phenyleneethynylene)s with multiple pendant ester groups in various lengths: Synthesis,photophysics and selective hydrolysis

Five fluorescence polymers with poly(perylene‐alt‐phenyleneethynylene)s (PPPEs) backbone and multiple side chains containing ester‐groups were synthesized via Sonogashira coupling reaction. These polymers were soluble in common organic solvents to form red‐orange solution. The polymer powders had dark red color. The absorption/emission spectra of these polymers were similar, with absorption bands between 300 and 600 nm and an emission peak between 520 and 700 nm. Furthermore, the ester groups of the side chains were partially or completely hydrolyzed, resulting in the fluorescence PPPEs with tunable density of carboxylic acid functional groups on the polymer chains as interaction/reaction sites for further applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1880–1886     

Revised insights into templating radical polymerization within nanoreactors

The field of polymer chemistry is currently experiencing major research efforts into development of novel techniques for synthesis of polymers with well‐controlled microstructure. Recently, a new method has been reported [McHale et al., Nat. Chem. 2012, 4, 491–497] whereby high molecular weight and low dispersity polymer can be obtained by a radical polymerization process via the use of solely physico‐chemical interactions. This work was based on the combination of H‐bonding templated polymerization confined within nanoreactors of self‐assembled block copolymers. Herein, this system is thoroughly investigated to fully elucidate the underlying mechanism. Modification of physico‐chemical parameters, kinetic parameters as well as observations of size exclusion chromatography (SEC) results and colloidal behavior in various solvents provide revised insights into the mechanism. Through detailed NMR and SEC investigations, it is demonstrated that the SEC secondary peak originally believed to be the high molecular weight “daughter” polymer actually corresponds to nanoparticles containing the daughter polymer. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1590–1600     

Synthesis,dynamic light scattering,and luminescence properties of copolymers containing iridium(III) bisterpyridine in the side chain

Supramolecular block‐random copolymers containing [Ir(terpy)₂]³⁺ in the side chain were synthesized via postfunctionalization of a P(S‐b‐AC_terpy) block copolymer. Absorbance and emission spectra compared to a model compound show that the polymer backbone has a minor effect on the polymer absorbance but produces a larger shift for the phosphorescence signals to higher wavelength. Dynamic light scattering of the metal complex containing copolymer studied in various solvents showed monomodal aggregation with decreasing aggregate size as the solvent dielectric constant increased. The copolymer precursor P(S‐b‐AC_terpy) shows multimodal aggregation in different solvents with the major population consisting of single chains. This difference in behavior between the two polymers is attributed to the electrolytic nature of the complex and the amphiphilicity induced by the charged metal complex. Supramolecular copolymers like these will continue to have interesting self‐organizational properties and may find applications in multicomponent systems for photoinduced charge separation processes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1109–1121, 2007     

Thermo‐responsive glycopolymer chains grafted onto honeycomb structured porous films via RAFT polymerization as a thermo‐dependent switcher for lectin Concanavalin a conjugation

Stable and surface‐modified films with regular porous arrays were created by crosslinking honeycomb structured porous films prepared via breath figures from poly(styrene‐co‐maleic anhydride). The formation of open or closed pores of the films was controlled by the addition of a polyion complex. Subsequent crosslinking of the films with 1,8‐diaminooctane led to films, which maintain their structure in solvents. In addition, excess amino functionality after crosslinking allowed the attachment of RAFT agent, 3‐benzylsulfanyl thiocarbonyl sulfanylpropionic acid, for the controlled surface polymerization of N‐isopropyl acrylamide (NIPAAm) and N‐acryloyl glucosamine (AGA). The attachment of thermo‐responsive glycopolymers onto the honeycomb structured porous films was confirmed using contact angle measurements and confocal fluorescence microscopy. Cleavage of surface anchored polymers via aminolysis revealed that the molecular weights of the surface grafted chains are significantly larger than the molecular weight of the chains generated in solution. The honeycomb structured porous films with their grafted PNIPAAm‐ran‐PAGA polymer chains showed selective recognition of Concanavalin A (ConA). Below the lower critical solution temperature (LCST) of the surface, the conjugation is switched off, while above the LCST the surface grafted glucose moieties bind strongly to ConA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3440–3455, 2010     

Synthesis and gas transport properties of random amide imide copolymers

Fully imidized random amide imide copolymers (rPAI) can be prepared in an aprotic solvent from trimellitic anhydride chloride (TMAc) and mixtures of various aromatic diamines via condensation polymerization. The polymers are soluble in a number of aprotic organic solvents including 1‐methyl‐2‐pyrrolidinone (NMP), N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide (DMF), and dimethylsulfoxide (DMSO). The gas transport properties of the rPAI materials are governed by the local structure around both the amide and imide linkages and can be tuned by the choice and ratio of diamines used. Significant improvement in selectivity relative to polyimides can be achieved. When inorganic carbonate salts are used to scavenge byproduct hydrogen chloride, the amount of residual salt in the dense films has a substantial effect on their gas transport properties. A fugitive salt process was identified, which eliminated this problem of residual inorganic salts. The activation energy for O₂, N₂, He, CO₂, and CH₄ permeability was determined for one of the copolymers. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1951–1965, 2000     

Synthesis and copolymerization of new phosphorus‐containing acrylates

Two phosphorus‐containing acrylate monomers were synthesized from the reaction of ethyl α‐chloromethyl acrylate and t‐butyl α‐bromomethyl acrylate with triethyl phosphite. The selective hydrolysis of the ethyl ester monomer with trimethylsilyl bromide (TMSBr) gave a phosphonic acid monomer. The attempted bulk polymerizations of the monomers at 57–60 °C with 2,2′‐azobisisobutyronitrile (AIBN) were unsuccessful; however, the monomers were copolymerized with methyl methacrylate (MMA) in bulk at 60 °C with AIBN. The resulting copolymers produced chars on burning, showing potential as flame‐retardant materials. Additionally, α‐(chloromethyl)acryloyl chloride (CMAC) was reacted with diethyl (hydroxymethyl)phosphonate to obtain a new monomer with identical ester and ether moieties. This monomer was hydrolyzed with TMSBr, homopolymerized, and copolymerized with MMA. The thermal stabilities of the copolymers increased with increasing amounts of the phosphonate monomer in the copolymers. A new route to highly reactive phosphorus‐containing acrylate monomers was developed. A new derivative of CMAC with mixed ester and ether groups was synthesized by substitution, first with diethyl (hydroxymethyl)phosphonate and then with sodium acetate. This monomer showed the highest reactivity and gave a crosslinked polymer. The incorporation of an ester group increased the rate of polymerization. The relative reactivities of the synthesized monomers in photopolymerizations were determined and compared with those of the other phosphorous‐containing acrylate monomers. Changing the monomer structure allowed control of the polymerization reactivity so that new phosphorus‐containing polymers with desirable properties could be obtained. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2207–2217, 2003