Journal of Polymer Science Part A: Polymer Chemistry

Depending on the monomer structure and reaction conditions, polycondensations of difunctional and tetrafunctional monomers may yield hyperbranched polymers, cyclic polymers with pendant functional groups, or multicyclic polymers (soluble nanogels).

A new triphenylamine-based polyamide with weight-average molecular weight (M_w = 63,400) and polydispersity index (PDI = 1.79) was prepared by direct polycondensation of AB-type monomer, 4-amino-4′-carboxy-4″-methoxytriphenylamine (4). The obtained polyamide showed excellent solubility in various organic polar solvents, and could be cast into transparent film with good thermal stability and relatively high glass-transition temperatures (282 °C). Cyclic voltammograms of the polyamide film cast onto an indium tin oxide coated glass substrate exhibited one oxidative redox couple at 0.72 V (oxidation onset potential) versus Ag/AgCl in an acetonitrile solution and revealed good stability of the electrochromic characteristic with a color change from colorless to green at applied potentials ranging from 0.00 to 1.10 V.

Iron-mediated activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) of styrene using a commercially available tris(3,6-dioxaheptyl)amine (TDA-1) as a novel ligand was conducted in bulk or solution in the presence of limited amount of air. The polymerizations show the features of “living”/controlled free-radical polymerizations, and well-defined polystyrenes with molecular weight M_n = 2400–36,500 g/mol and narrow polydispersity (M_w/M_n = 1.11–1.29) were obtained. The living feature of the obtained polymer was further verified by a chain-extension experiment. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Star-shaped polypeptide/glycopolymer biohybrids were synthesized by combining ROP and ATRP. Independent of weight fraction of glycopolymer, large spherical micelles were fabricated in aqueous solution; meanwhile, the poly(L-glutamate)/glycopolymer hybrid exhibited a pH-sensitive self- assembly. Whatever these biohybrids existed in unimolecular level or glycopolymer-surfaced aggregates, they had specific biomolecular recognition with Con A. Star-shaped biohybrids showed a higher doxorubicin loading efficiency and longer drug-release time than linear analogues. This potentially provides a platform for fabricating targeted anticancer drug delivery system and studying glycoprotein functions in vitro. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

A series of novel benzimidazole-containing aromatic polyimides were prepared and characterized. Without any stretching, the films showed high levels of tensile modulus of up to 5.6 GPa and high T_gs of up to 425 °C. Excellent properties were proved to be attributed to the rigid-rod structure and hydrogen bond of inter-macromolecular, which caused self-molecular orientation and the formation of densely packed layered ribbon-like morphology. High degree of supramolecular order led to the increase of thermal stability and mechanical properties of the polyimide films.

A novel glycopolymer, P(VB-D-ManaH-co-AAm), was prepared by the copolymerization of a new glycomonomer having D-mannaric moieties, VB-D-ManaH, with acrylamide. The resulting glycopolymer and VB-D-ManaH were found to inhibit the β-glucuronidase activity, although D-mannaro-1,4:6,3-dilactone (D-MDL) was known not to do. Additionally, the inhibition ability of P(VB-D-ManaH-co-AAm) was much higher than that of VB-D-ManaH, which was caused by the polymeric cluster effect. Thus, P(VB-D-ManaH-co-AAm) and VB-D-ManaH may be the first D-mannaric strong inhibitors to the β-glucuronidase activity. Lineweaver–Burk plot suggests that the inhibition mechanism of P(VB-D-ManaH-co-AAm) and VB-D-ManaH were not so simple.

Two strategies to obtain a SAFC electrode binder were chosen: First, the radical copolymerization of CTFE with DADMAC, and second, the partial replacement of the Cl⁻ counterions of poly(DADMAC) by bistrifluoromethanesulfonimide (TFSI⁻), and then OH⁻. When used in the membrane-electrode assembly (MEA), significant improvements were noted (a 50% increase of the OCV, a 500% increase in current density and a 540% increase in accessible power).

A new type of monoquaternary cationic polymerizable surfactants was prepared based on the piperazine heterocycle. These surfactants were polymerized in micellar and isotropic conditions. The polymers prepared in micellar condition displayed high-molar mass and hence a higher viscosity than that prepared in isotropic conditions. These surfactants formed stable ternary microemulsion, and cross-linked gels were prepared by photo-polymerization in microemulsion condition. The gels were highly sensitive to changes in pH of the medium. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Novel CPDT-based copolymers employing arylcyanovinyl and keto groups in different molar ratios by palladium (0)- catalyzed Suzuki coupling reactions. The polymers showed broad optical absorption from 400 to 900 nm with optical band gaps at 1.38–1.70 eV. Polymer solar cells were fabricated using [6,6]-phenyl C₆₁ butyric acid methyl ester (PCBM) as an electron acceptor, and the device of copolymer P1 produced the highest preliminary result having a quite high open-circuit voltage of 0.84 V, a short-circuit current of 2.36 mA/cm², a fill factor of 0.38, and an energy conversion efficiency of 0.77%.

The random poly(arylene-vinylene)s P1–5 containing the 3,7-dibenzothiophene-5,5-dioxide unit were synthesized by the Suzuki–Heck cascade polymerization reaction. In the solid state, P1 show λ_em ranging from 578 to 608 nm. The presence, in the copolymer primary structure, of the 3,7-dibenzothiophene-5,5-dioxide units in amounts higher than 10%, stabilizes the electron charged states as revealed by the quasi-reversibility of the CV reduction scans. The properties of yellow to yellow–green emitting OLED devices were measured for all polymers. The best performances were obtained for the devices with ITO/PEDOT-PSS/P4/Alq₃/Ca/Al configuration (1835 cd/m² 0.25 cd/A at 14 V).

Spherical nanoparticles consisted of coacervate core-POE shell structure with mean diameters from 60 to 600 nm are obtained by polyelectrolyte complex formation between polyampholytic chitosan derivative N-carboxyethylchitosan and POE-b-PDMAEMA double hydrophilic block copolymers with weak polycationic sequence. Their high pH-sensitivity, the presence of a POE shell and the use of natural polymer make them promising candidates for application in the biomedical and diagnostic practice.

A series of novel triphenylamine-based polymers were synthesized from benzaldehyde and triphenylamine derivatives. All the polymers having high molecular weight are readily soluble in many organic solvents and could be solution-cast into amorphous films. They had glass transition temperatures (T_gs) in the range of 193–217 °C, and 10% weight loss temperatures in excess of 475 °C. Cyclic voltammograms of all polymers showed reversible oxidation redox peaks and E_onset around 0.42–0.90 V, indicating that the polymers are electrochemically active. In addition, all these polymers revealed photochemical characteristics in conformity to their electrochromic characteristics. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.].

A star-shaped poly(1,3-cyclohexadiene) (PCHD) with a fullerene-C₆₀ (C₆₀) core (C₆₀-PCHD) was prepared to examine the thermal stability. The covalent bond between the C₆₀ and PCHD arm formed by a 1,2-cyclohexadiene (CHD) unit on the C₆₀ was stronger than that formed by a 1,4-CHD unit. The double bond in the CHD unit adjoining the C₆₀ core was a key structure. The hydrogenated C₆₀-PCHD, which did not contain a double bond, possessed significantly higher thermal stability compared with C₆₀-PCHD. The mechanism of elimination of PCHD arm molecules from the C₆₀ core was thought to proceed via a 1,5-sigmatropic H-shift.

Main chain photoactive liquid crystalline polyethers were synthesized and studied for individual and combined effects of spacer and substituents on mesogenic and photoactive properties. Drastic reduction of transition temperatures was observed with combined increase of both. The width of the liquid crystalline phase reduced with increasing number of methoxy substituents on the mesogenic unit. The effect of spacer on photocycloaddition was negligible and steric hinderance caused by increasing the number of substituents decreased photoreactivity. Total energies of crosslinked dimers calculated from modeling studies supported the photoactivity results. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Predominant alternating copolymers of methyl acrylate and 1-octene were free radically synthesized using Montmorillonite K10 powder clay as Lewis acid at 70 °C. The transparent polymers were true copolymers as analyzed from the monomodal curve obtained in gel permeation chromatography. The usage of solid acid clay as Lewis acid led to increase in total percentage conversion along with increased incorporation of alkene unit. The alternation in the sequence of monomer units was present irrespective of the copolymer composition which was substantiated through 2D HMQC in conjugation with TOCSY NMR experiments.

Novel donor-acceptor type polymers consisting of alternating quaterthiophene and an electron withdrawing pyrazinyl or pyridinyl moieties were successfully prepared using Stille coupling approach. All the polymers are highly soluble in common organic solvents such as THF and chloroform. The polymer having pyrazine unit exhibited a red-shift in both absorption and emission in comparison with those analogues containing pyridine because of the strong electron withdrawing character of pyrazinyl group. The polymer containing pyrazinyl as acceptor units also depicted decrease in its optical and electrochemical bandgap relative to those polymers containing pyridine moieties. The electrochemical behavior showed facile n-doping and p-doping properties of those polymers. A field-effect mobility of 8.5 × 10⁻⁴ cm²/V·s and an on/off current ratio of 4 × 10³ were observed in FET devices made from thin film of the polymer having pyrazine unit.

In this article, we investigated the possibility to develop a new bioinspired synthetic route based on the enzymatic polymerization of isopentenyl pyrophosphate, to give access to Natural Rubber-like elastomers. Based on elementary processes present in nature, the synthesis of polyisoprene based on carbocationic polymerization initiated by dimethyl allyl bromide (DMABr)/TiCl₄ was studied. It is shown that using this strategy, 1,4-oligoisoprene carrying a dimethyl allyl head group is produced in both cis and trans configurations, together with cyclized sequences. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Following the elementary processes occurring in the enzymatic Natural Rubber biosynthesis, the synthesis of polyisoprenes based on the carbocationic polymerization of isoprene initiated by dimethyl allyl alcohol (DMAOH) and TiCl₄ or BF₃.Et₂O as catalyst is studied. It is shown that using this bio-inspired strategy, 1,4-oligoisoprene carrying a dimethyl allyl head group is produced in both cis and trans configurations, together with cyclized sequences. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

Synthesis of poly(styrene-block-tetrahydrofuran) (PSt-b-PTHF) block copolymer on the surfaces of intercalated and exfoliated silicate (clay) layers by mechanistic transformation was described. First, the polystyrene/montmorillonite (PSt/MMT) nanocomposite was synthesized by in situ atom transfer radical polymerization (ATRP) from initiator moieties immobilized within the silicate galleries of the clay particles. Transmission electron microscopy (TEM) analysis showed the existence of both intercalated and exfoliated structures in the nanocomposite. Then, the PSt-b-PTHF/MMT nanocomposite was prepared by mechanistic transformation from ATRP to cationic ring opening polymerization (CROP). All nanocomposites exhibit enhanced thermal stabilities compared with the virgin polymer segments. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.].

The anionic polymerization of butadiene initiated with 1,4-dilithio-1,1,4,4-tetraphenylbutane in diethyl ether (DEE) gives polybutadiene (PBD) with high 1,2 content, narrow polydispersities, and predicted molecular weights (denoted in blue). In THF, this polymerization does not work very well (denoted in red). PBD dianion is end capped quantitatively by addition of 1,1-diphenylethylene (DPE) in the presence of THF. Subsequent addition of methyl methacrylate (MMA) at low temperatures gives well-defined PMMA-b-PBD-b-PMMA triblock copolymers (denoted by blue SEC curve). The results are accounted for by taking into consideration the effects of Li ion solvation on the BD initiation and end capping of the PBD anion by DPE. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.].

A combination of ATRP and RAFT Hetero Diels–Alder (HDA) conjugation is employed to efficiently generate well-defined star blockcopolymers in a facile fashion. The presented approach demonstrates the versatility of the RAFT-HDA click methodology. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]

3-Isochromanone (ICM), an aromatic lactone, underwent cationic ring opening polymerization to give a poly(phenylene-methylene) having a carboxyl acid moiety in the side chain. The polymerization of ICM proceeded through the formation of benzyl cationic intermediate and its successive Friedel-Crafts reaction. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]