Journal of Polymer Science Part A: Polymer Chemistry

The image shows a typical oily streak texture of the cholesteric phase at 171°C for monomer M₄. On page 5049, Jian-She Hu, Dan Li, Wen-Chang Zhang, and Qing-Bao Meng present the synthesis of four new chiral monomers and polymers based on menthol. Their chemical structures, phase behavior, and thermal stability are characterized by FT-IR, NMR, DSC, POM, XRD, and TGA. By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, the target monomers and polymers can form the SmC*, cholesteric, and SmA phases. By increasing the mesogenic core rigidity, the corresponding T_m, T_g, and T_i increased. In addition, increasing the spacer length decreased the T_m and T_g, while T_i increased.

Polyacetylenes are formed upon irradiation with gamma rays of ortho-substituted aryl alkynes 2-RC₆H₄C≡CH (R = CF₃, OMe, Me) in methanol solutions. An osmosis driven manipulation allows the soluble polymers to aggregate in the form of nanospheres, as well as hollow nanospheres, of different dimensions. The finding and development of this transition metal-free activation process of terminal alkynes come from the collaboration of three research groups with authors Mauro Bassetti, Ilaria Fratoddi, Laura Lilla, Chiara Pasquini, Maria Vittoria Russo, and Ornella Ursini, as presented on page 5097. The SEM image in the picture highlights the shape and size of the nanoparticles obtained via the osmosis-based methodology for one of these polymers (R = CF₃).

Sn(0)-mediated SET-LRP of AN with CCl₄ as initiator and HMTA as ligand in DMF was studied. The polymerization obeyed first order kinetics. The molecular weight of PAN increased linearly with monomer conversion and PAN exhibited narrow molecular weight distributions. The block copolymer PAN-b-polymethyl methacrylate was successfully obtained.

Two novel crosslinked poly(amidoamine)s carrying amine and carboxyl groups in their repeating units, LYMA and LMT85, were prepared and studied as heavy metal ions absorbing resins. The heavy metal ions considered were Cu²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Ni²⁺, and Co²⁺. LYMA selectively absorbed Cu²⁺ and Ni²⁺, whereas LMT85 was capable of absorbing all the ions rapidly and quantitatively. The absorption process was reversible and the resins were easily regenerated by acidification.

Among P1–P3, polymer P3 (with H-bonds) revealed the best electrochromic property with the most noticeable color change, and possessed the highest power conversion efficiency (PCE) value of 0.61%. In contrast to P2 (without H-bands), the thermal stability, crystallinity, and electrochromism along with the photovoltaic properties of P3 were generally enhanced due to its H-bonded effects.

A series of side-chain liquid-crystalline polymers, named Poly(n-POMS) (n refers to the carbon number of the alkyl tails), has been synthesized, which is constructed with the flexible rod-like benzyl ether mesogens attached directly onto the polyethylene backbone. The liquid crystallinity of Poly(n-POMS) is dependent on the length of alkyl tail. When n ≥ 8, the polymers can form bilayer smectic A phases with the layer thickness up to 5 nm, which is partially attributed to the flexible rod-like mesogens that canadjust properly their conformation to fit in the mesophase.

A novel porphyrin-incorporated polymer, PPor-DITT, was synthesized, characterized, and used as a blue-light-harvesting dopant in the ternary-blend PSCs. Doping PPor-DITT in an amorphous host (PTPTPTDPP) leverages the strong 400–550 nm absorption band of PPor-DITT and circumvents the difficulties in reaching optimized morphology in the PPor/PCBM thin films. An addition of 2 wt % of PPor-DITT in PPor-DITT:PTPTPTDPP:PC₇₁BM ternary-blend PSCs resulted in a 10% increase of EQE in the blue-light region, and the value of FF was well sustained.

The first successful living cationic polymerization of a vinyl ether with a naphthyl group [2-(2-naphthoxy)ethyl vinyl ether, βNpOVE] was performed using base-assisting initiating systems with a Lewis acid. The Et_1.5AlCl_1.5/1,4-dioxane or ethyl acetate system induced living cationic polymerization of βNpOVE in toluene at 0 °C. On the other hand, the reaction of α-substituted monomer was accompanied with appreciable side reactions. The glass transition temperatures of poly(NpOVE)s are higher by approximately 40 °C than that of poly(2-phenoxyethyl vinyl ether).

New chiral liquid crystal monomers (M₁–M₄) and homopolymers (P₁–P₄) with the same terminal menthyl group were designed and prepared. M₁ and M₂ all showed the cholesteric phase, whereas their corresponding P₁ and P₂ showed the more ordered SmA phase. However, M₃ and M₄ with stronger rigidity of mesogenic core revealed a SmC* phase, cholesteric phase, and cubic blue phase, respectively, and their corresponding P₃ and P₄ all showed the SmC* phase and SmA phase. The T_m,T_g, and T_i of the target monomers and polymers increased with increasing mesogenic core rigidity. The T_m and T_gdecreased, whereas T_i increased with increasing spacer length.

The amphiphilic rod-coil conjugated block copolymers, poly(3-hexylthiophene)-b-poly (ethylene oxide) (P3HT-b-PEO) were synthesized via a facile click reaction. The subtle balance between microphase separation of copolymer and the π-π stacking of the conjugated P3HT can be controlled by changing the solvents of different selectivity in solution.

The development of a novel polymer for which the fluorescence intensity can be controlled by electrochemical methods is presented. The blue light emitting fluorescent behavior of the polymer could be reversibly switched between the non-fluorescence (oxidized) state and the strong fluorescence (neutral) state with a high contrast ratio (I_f/I_f0) of 16.3. The role of the electrochemical oxidation of the triphenylamine moieties is to generate the corresponding radical cations that lead to fluorescence quenching in the solid matrix.

The shape of self-assembling polymer–drug conjugates is important for effective drug delivery. In this study, polymeric drug conjugates of different morphologies are synthesized with phytosphigonsine (PHS) as a hydrophobic model drug and poly(amino acid) as a hydrophilic host polymer. By varying the degree of PHS substitution, spherical and worm-like micelle structures of PHS–poly(amino acid) conjugates were formed. Along with physicochemical properties, an in vitro study including cellular uptake, cytotoxicity, and cell cycle was investigated.

Magnetite nanoparticles coated with glycopolymer were designed by a simple and effective method. The defined hydrophobic magnetite nanoparticles with an average size of 17 ± 2 nm were modified at the surface by the incorporation of active vinyl groups. Then, the radical polymerization of the glycomonomer was carried out using the magnetite nanoparticles as seeds. The resultant hybrid nanoparticles were water dispersible presenting high density of carbohydrates at the surface, specific binding to Concanavalin A protein and adequate magnetic properties that would make them suitable for intracellular hyperthermia applications.

Arylacetylenes featuring ortho-substituents (CF₃, OMe, Me) are polymerized upon exposure to gamma radiation in methanol solution at ambient temperature in the absence of metal or radical initiators. The derived polyarylacetylenes, which are fully redissolvable in organic solvents, exhibit lower molecular weights and similar spectroscopic and thermal features to those derived from transition metal catalysts. The materials, when subjected to osmosis driven self-aggregation, separate as nanospheres or hollow nanospheres depending on the solvent/non-solvent couple.

Three types of bi-functionalized copolymers (P1FAz, P2FAz, and P3FAz) with different numbers of fluorene units and an azobenzene unit were synthesized and characterized using UV&#150>;visible and polarized absorption spectroanalysis. Photo-induced alignment was achieved using the P1FAz film after irradiation with linear polarized 400 nm light and subsequent annealing at 60 °C.

A novel benzoxazine monomer containing a benzoxazole group DAROH-a was synthesized using a nonsolvent method. The ring-opening polymerization of the DAROH-a monomer was investigated with differential scanning calorimetry in dynamic conditions and in situ Fourier transform infrared spectroscopy. Its corresponding crosslinked polybenzoxazine poly(DAROH-a) shows an ordered texture, a higher glass transition temperature, and good thermal properties. Furthermore, the dielectric constant of poly(DAROH-a) is very low. Meanwhile, the dielectric constants and dielectric loss of poly(DAROH-a) at the same frequency barely change at different temperatures.

Due to different B₃-type comonomers in “A₂+B₃” type NLO hyperbranched polymers, the Ar-Ar^F self-assembly effect in the interior of these polymers were much different, leading to the different trends of the NLO activities. P2 with the triphenylamine as comonomer, which satisfy the conditions that self-assembly effect between the pentafluoroaromatic moieties and comonomers, demonstrated much larger NLO effect and better stability than its analog P1, only containing normal phenyl as isolation groups.

Four novel chiral phenylacetylenes having an L-amino alcohol residue and two hydroxymethyl groups were synthesized and polymerized by Rh catalysts. One of the chiral monomers that has an L-valinol residue and two hydroxy groups was found to be suitable for both modes of asymmetric polymerization, that is, the helix-sense-selective polymerization (HSSP) and the asymmetric-induced polymerization (AIP). This represents the first example of such a monomer. The monomers having an L-alaninol and L-tyrosinol were suitable to neither HSSP nor AIP, and a monomer having L-phenylalaninol was suitable only to AIP. The substituent R largely affected the asymmetric polymerizations.

The graft polymers PI-g-PI, PI-g-PS, PI-g-(PI-b-PS), and PI-g-(PS-b-PI) were synthesized by LAP mechanism and coupling reaction between epoxide and macroanions of PI⁻Li⁺, PS⁻Li⁺, PS-b-PI⁻Li⁺, or PI-b-PS⁻Li⁺, respectively. This work provided a versatile and efficient route to synthesize the graft polymers with PI as main chain. Especially, the molecular weight of main chain and side chains, the sequence of side chains, and the grafting ratio could all be well modulated elaborately.

An hybrid triblock copolymer based on a central block consisting of a microbically produced poly[(R)-3-hydroxybutyrate] (PHB) and two terminal polystyrene (PS) blocks was prepared by atom transfer radical polymerization of styrene. A bifunctionally activated PHB macroinitiator, as attained by reaction of the di-hydroxy end-capped PHB with α-bromoisobutyryl chloride, was used as promoter of styrene polymerization at the opposite sides of the PHB block. The prepared PS–PHB–PS triblock copolymer was tested as compatibilizer at three different contents (10, 20, and 33% by weight) of equiponderal blends of PHB/PS.

A silacyclobutane monomer having a five-membered cyclic carbonate structure (SBMC) and a difunctional silacyclobutane crosslinker (HMBS) were prepared, and their polymerization was investigated. Polycarbosilane-based gel electrolytes were prepared and applied to lithium ion batteries.

A versatile approach based on thiol–ene reaction has been developed for the synthesis of polyphosphazene derivatives with diverse functional groups (hydroxy acid, hydroxyl, and glucosyl). Despite the high and quantitative conversions that were achieved in theresulting products, the steric size of thiols had an effect on the reaction rate.

Oligo(carbonate-ether) diol with number average molecular weight below 2000 g mol⁻¹ was controllably synthesized in high activity by Zn-Co-DMCC catalyzed immortal copolymerization of CO₂/PO with dicarboxylic acid as chain transfer agent. The number average molecular weight was in linear relationship to the molar ratio of PO/dicarboxylic acid and thus can be precisely controlled with narrow molecular weight distributions (MWDs: 1.11–1.41), and the carbonate unit content can be tunable between 40% and 75% by simply altering the reaction condition.

5-norbornene-2-ethyl ester (mixture of endo and exo) is polymerized via ring-opening metathesis polymerization, yielding polymers with molecular weights ranging from 50,000 to 5,000,000 g/mol. The polymers are hydroxylated and saponified without alteration of the molecular weight. The polymers are analyzed by NMR, GPC, DSC, and TGA. Films are cast from the polymers at several molecular weights and their rheological properties are investigated. The results showed greater solid-like character with increasing molecular weight for all polymers analyzed and minimal cytotoxicity.

In this work, a robust technique for the preparation of degradable nanoparticles with tunable hydrophobicity and degradation kinetics via starved emulsion free-radical polymerization is proposed. This advanced method allows producing tailor-made PLA-based nanoparticles with size down to 25 nm and narrow polydispersity index. These novel NPs can be potentially used as a new vector for different biomedical applications.

The terminal alkyne and azide groups were successfully introduced onto the cellulose and chitosan chains, respectively. Subsequently, the cellulose-click-chitosan polymer was first synthesized via the Cu(I)-catalyzed 1,3-Huisgen cycloaddition click reaction. Interestingly, some hollow tubes were observed by SEM.