Thin films of PS/PS‐b‐pnipam and ps/pnipam polymer blends with tunable wettability

We developed thin films of blends of polystyrene (PS) with the thermoresponsive polymer poly(N‐isopropylacrylamide) (PNIPAM) (PS/PNIPAM) and its diblock copolymer polystyrene‐b‐poly(N‐isopropylacrylamide) (PS/PS‐b‐PNIPAM) in different blend ratios, and we study their surface morphology and thermoresponsive wetting behavior. The blends of PS/PNIPAM and PS/PS‐b‐PNIPAM are spin‐casted on flat silicon surfaces with various drying conditions. The surface morphology of the films depends on the blend ratio and the drying conditions. The PS/PS‐b‐PNIPAM films do not show an increase in their water contact angles with temperature, as it is expected by the presence of the PNIPAM block. All PS/PNIPAM films show an increase in the water contact angle above the lower critical solution temperature of PNIPAM, which depends on the ratio of PNIPAM in the blend and is insensitive to the drying conditions of the films. The difference between the wetting behavior of PS/PS‐b‐PNIPAM and PS/PNIPAM films is due to the arrangement of the PNIPAM chains in the film. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 670–679     

Polystyrene‐b‐poly(2,2,2‐trifluoroethyl acrylate)‐b‐polystyrene copolymers: Synthesis and fabrication of their hydrophobic porous films,spheres, and fibers

New block copolymers Polystyrene‐b‐poly (2,2,2‐trifluoroethyl acrylate)‐b‐Polystyrene (PS‐PTFEA‐PS) with controlled molecular weight (M_n=5000‐11000 g?mol^?1) and narrow molecular weight distribution (M_w/M_n=1.13‐1.17) were synthesized via RAFT polymerization. The molecular structure and component of PS‐PTFEA‐PS block copolymers were characterized through ¹H NMR, ¹⁹F NMR, GPC, FT‐IR and elemental analysis. The porous films of such copolymers with average pore size of 0.80‐1.34 μm and good regularity were fabricated via a static breath‐figure (BF) process. The effects of solvent, temperature, and polymer concentration on the surface morphology of such film were investigated. In addition, microstructured spheres and fibers of such block copolymers were fabricated by electrospinning process and observed by scanning electron microscopy (SEM). Furthermore, the hydrophobicity of porous films, spheres, and fibers was investigated. The porous film showed a good hydrophobicity with the water‐droplet contact angles of 129°, and the fibers showed higher hydrophobicity with the water‐droplet contact angles of 142°. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 678–685     

Synthesis of nitroxide‐containing block copolymers for the formation of organic cathodes

This contribution describes the polymerization of 2,2,6,6‐tetramethylpiperidin‐4‐yl methacrylate by atom transfer radical polymerization (ATRP). Different catalytic systems are compared. The CuCl/4,4′‐dinonyl‐2,2′‐dipyridyl catalytic system allows a good control over the polymerization and provides polymers with a polydispersity index below 1.2. The successful polymerization of styrene from PTMPM‐Cl macroinitiators by ATRP is then demonstrated. Successful quantitative oxidation of PTMPM‐b‐PS block copolymers leads to poly(2,2,6,6‐tetramethylpiperidinyloxy‐4‐yl‐methacrylate)‐b‐poly(styrene) (PTMA‐b‐PS). The cyclic voltammogram of PTMA‐b‐PS indicates a reversible redox reaction at 3.6 V (vs. Li⁺/Li). Such block copolymers open new opportunities for the formation of functional organic cathode materials. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

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     

Ternary Donor–Insulator–Acceptor Systems for Polymer Solar Cells

A series of block copolymers with fixed length of the semiconductor‐block poly(3‐butylthiophene) (P3BT) and varying length of the insulator‐block polystyrene (PS) are synthesized. These copolymers are blended with phenyl‐C61‐butyric acid methyl ester (PCBM) for the bulk heterojunction photoactive layers. With appropriate insulator‐block length and donor–acceptor ratio, the power conversion efficiency increases by one order of magnitude compared with reference devices with pure P3BT/PCBM. PS blocks improve the miscibility of the active layer blends remarkably. The P3BT‐b‐PS crystallizes as nanorods with the P3BT core covered with the PS‐block, which creates a nanoscale tunneling barrier between donor and acceptor leading to more efficient transportation of charge carriers in the semiconductors.     

Synthesis of poly(tetrahydrofuran)‐b‐polystyrene block copolymers from dual initiators for cationic ring‐opening polymerization and atom transfer radical polymerization

A dual initiator (4‐hydroxy‐butyl‐2‐bromoisobutyrate), that is, a molecule containing two functional groups capable of initiating two polymerizations occurring by different mechanisms, has been prepared. It has been used for the sequential two‐step synthesis of well‐defined block copolymers of polystyrene (PS) and poly(tetrahydrofuran) (PTHF) by atom transfer radical polymerization (ATRP) and cationic ring‐opening polymerization (CROP). This dual initiator contains a bromoisobutyrate group, which is an efficient initiator for the ATRP of styrene in combination with the Cu(0)/Cu(II)/N,N,N′,N″,N″‐pentamethyldiethylenetriamine catalyst system. In this way, PS with hydroxyl groups (PS‐OH) is formed. The in situ reaction of the hydroxyl groups originating from the dual initiator with trifluoromethane sulfonic anhydride gives a triflate ester initiating group for the CROP of tetrahydrofuran (THF), leading to PTHF with a tertiary bromide end group (PTHF‐Br). PS‐OH and PTHF‐Br homopolymers have been applied as macroinitiators for the CROP of THF and the ATRP of styrene, respectively. PS‐OH, used as a macroinitiator, results in a mixture of the block copolymer and remaining macroinitiator. With PTHF‐Br as a macroinitiator for the ATRP of styrene, well‐defined PTHF‐b‐PS block copolymers can be prepared. The efficiency of PS‐OH or PTHF‐Br as a macroinitiator has been investigated with matrix‐assisted laser desorption/ionization time‐of‐flight spectroscopy, gel permeation chromatography, and NMR. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3206–3217, 2003     

Synthesis and characterizations of the four‐armed amphiphilic block copolymer S[poly(2,3‐dihydroxypropyl acrylate)‐block‐poly(methyl acrylate)]4

The polymers poly[(2,2‐dimethyl‐1,3‐dioxolane‐4yl) methyl acrylate] (PDMDMA) and four‐armed PDMDMA with well‐defined structures were prepared by the polymerization of (2,2‐dimethyl‐1,3‐dioxolane‐4yl) methyl acrylate (DMDMA) in the presence of an atom transfer radical polymerization (ATRP) initiator system. The successive hydrolyses of the polymers obtained produced the corresponding water‐soluble polymers poly(2,3‐dihydroxypropyl acrylate) (PDHPA) and four‐armed PDHPA. The controllable features for the ATRP of DMDMA were studied with kinetic measurements, gel permeation chromatography (GPC), and NMR data. With the macroinitiators PDMDMA–Br and four‐armed PDMDMA–Br in combination with CuBr and 2,2′‐bipyridine, the block polymerizations of methyl acrylate (MA) with PDMDMA were carried out to afford the AB diblock copolymer PDMDMA‐b‐MA and the four‐armed block copolymer S{poly[(2,2‐dimethyl‐1,3‐dioxolane‐4yl) methyl acrylate]‐block‐poly(methyl acrylate)}₄, respectively. The block copolymers were hydrolyzed in an acidic aqueous solution, and the amphiphilic diblock and four‐armed block copolymers poly(2,3‐dihydroxypropyl acrylate)‐block‐poly(methyl acrylate) were prepared successfully. The structures of these block copolymers were verified with NMR and GPC measurements. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3062–3072, 2001     

Preparation of main‐chain imidazolium‐functionalized amphiphilic block copolymers through combination of condensation polymerization and nitroxide‐mediated free radical polymerization and their micelle study

Main‐chain imidazolium‐functionalized amphiphilic block copolymers (PIL‐b‐PS) consisting of polyionic liquid (PIL) and polystyrene (PS) blocks have been first synthesized by condensation polymerization combined with nitroxide‐mediated free radical polymerization (NMP). The di‐functional imidazolium‐based ionic liquid (IL) having both hydroxyl and ester end groups was synthesized through Michael addition between imidazole and methylacrylate (MA) and further quaternization by 2‐chloroethanol. The HTEMPO (4‐hydroxy‐2,2,6,6‐tetramethyl‐1‐piperidinyloxy) terminated polyionic liquid (HTEMPO‐PIL) as the hydrophilic block was prepared by condensation polymerization of di‐functional imidazolium IL and HTEMPO at a certain ratio. The hydrophobic PS block was synthesized by controlled radical polymerization of styrene using HTEMPO‐PIL through NMP, resulting PIL‐b‐PS block copolymers. The structure of block copolymers obtained has been characterized and verified by FTIR, ¹H NMR, and size exclusion chromatography analyses. In addition, the morphology and size of the micelles formed by PIL‐b‐PS block copolymers in water were investigated by transmission electron microscopy and dynamic light scattering. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Selective control over the lamellar thickness of one domain in thin binary blends of block copolymer films

Thin binary blends of poly(styrene‐b‐methyl methacrylate) (PS‐PMMA) block copolymers in films where the lamellar thickness of one domain is controlled while preserving the thickness of the other domain were demonstrated without microphase separation. One of the block copolymers used here was short and symmetric, and the other was long and asymmetric; the molecular weights of the PMMA block chains in the constituents were similar. A random copolymer brush was introduced and film thickness and composition of brush were adjusted to induce perpendicular orientation in thin film. As the blend composition of the long asymmetric block copolymer increased, the PS lamellar thickness increased from 15.8 to 25.1 nm, whereas the PMMA lamellar thickness remained constant at approximately 14 nm (the thickness decreased slightly from 14.0 to 13.3 nm). The domain spacing behavior in thin film was consistent in the bulk. These results were compared with the Birshtein, Zhulina, and Lyatskaya model and the theories for pure block copolymers in the strong segregation limit and in the intermediate segregation regime. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1393–1399     

Formation of Polyolefin‐block‐polystyrene Block Copolymers on Phenoxyimine Catalysts

Summary: PE‐block‐PS and P(E‐co‐P)‐block‐PS block copolymers were synthesised via sequential monomer addition during homogeneous polymerisation on various phenoxyimine catalysts. One phenoxyimine catalyst was tailored to produce high molecular weight block copolymers containing both, polyolefin and polystyrene segments. According to chromatographic analysis and TEM morphology studies, blends of block copolymers and PE homopolymers [or P(E‐co‐P), respectively] were formed. The direct olefin/styrene block copolymer synthesis on phenoxyimine catalysts represents an attractive, new one‐pot route to styrenic block copolymers which are commercially prepared by anionic styrene/diene block copolymerisation followed by hydrogenation.

     

Organizing thermodynamic data obtained from multicomponent polymer electrolytes: Salt‐containing polymer blends and block copolymers

The objective of this review is to organize literature data on the thermodynamic properties of salt‐containing polystyrene/poly(ethylene oxide) (PS/PEO) blends and polystyrene‐b‐poly(ethylene oxide) (SEO) diblock copolymers. These systems are of interest due to their potential to serve as electrolytes in all‐solid rechargeable lithium batteries. Mean‐field theories, developed for pure polymer blends and block copolymers, are used to describe phenomenon seen in salt‐containing systems. An effective Flory–Huggins interaction parameter, χ_eff , that increases linearly with salt concentration is used to describe the effect of salt addition for both blends and block copolymers. Segregation strength, χ_effN , where N is the chain length of the homopolymers or block copolymers, is used to map phase behavior of salty systems as a function of composition. Domain spacing of salt‐containing block copolymers is normalized to account for the effect of copolymer composition using an expression obtained in the weak segregation limit. The phase behavior of salty blends, salty block copolymers, and domain spacings of the latter systems, are presented as a function of chain length, composition and salt concentration on universal plots. While the proposed framework has limitations, the universal plots should serve as a starting point for organizing data from other salt‐containing polymer mixtures. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1177–1187     

Synthesis and characterization of six‐arm star polystyrene‐block‐poly (3‐hexylthiophene) copolymer by combination of atom transfer radical polymerization and click reaction

A novel six‐arm star block copolymer comprising polystyrene (PS) linked to the center and π‐conjugated poly (3‐hexylthiophene) (P3HT) was successfully synthesized using a combination of atom transfer radical polymerization (ATRP) and click reaction. First, star‐shaped PS with six arms was prepared via ATRP of styrene with the discotic six‐functional initiator, 2,3,6,7,10,11‐hexakis(2‐bromoisobutyryloxy)triphenylene. Next, the terminal bromides of the star‐shaped PS were substituted with azide groups. Afterward, the six‐arm star block copolymer PS‐b‐P3HT was prepared using the click coupling reaction of azide‐terminated star‐shaped PS with alkynyl‐terminated P3HT. Various techniques including ¹H NMR, Fourier‐transform infrared and size‐exclusion chromatography were applied to characterize the chemical structures of the intermediates and the target block copolymers. Their thermal behaviors and optical properties were investigated using differential scanning calorimetry and UV–vis spectroscopy. Moreover, atomic force microscopy (AFM) was utilized to observe the morphology of the star block copolymer films. In comparison with two linear diblock copolymer counterparts, AFM results reveal the effect of the star block copolymer architecture on the microphase separation‐induced morphology in thin films. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Amphiphilic block and statistical copolymers with pendant glucose residues: Controlled synthesis by living cationic polymerization and the effect of copolymer architecture on their properties

Amphiphilic block and statistical copolymers of vinyl ethers (VEs) with pendant glucose residues were synthesized by the living cationic polymerization of isobutyl VE (IBVE) and a VE carrying 1,2:5,6‐di‐O‐isopropylidene‐D ‐glucose (IpGlcVE), followed by deprotection. The block copolymer was prepared by a two‐stage sequential block copolymerization, whereas the statistical copolymer was obtained by the copolymerization of a mixture of the two monomers. The monomer reactivity ratios estimated with the statistical copolymerization were r₁ (IBVE) = 1.65 and r₂ (IpGlcVE) = 1.15. The obtained statistical copolymers were nearly uniform with the comonomer composition along the main chain. Both the block and statistical copolymers had narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight ∼ 1.1). Gel permeation chromatography, static light scattering, and spin–lattice relaxation time measurements in a selective solvent revealed that the block copolymer formed multimolecular micelles, possibly with a hydrophobic poly(IBVE) core and a glucose‐carrying poly(VE) shell, whereas the statistical copolymer with nearly the same molecular weight and segment composition was molecularly dispersed in solution. The surface properties of the solvent‐cast films of the block and statistical copolymer were also investigated with the contact‐angle measurement. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 459–467, 2001     

Antimicrobial polymers containing melamine derivatives. II. Biocidal polymers derived from 2‐vinyl‐4,6‐diamino‐1,3,5‐triazine

Poly(2‐vinyl‐4,6‐diamino‐1,3,5‐triazine) (PVDAT) and a series of poly(styrene‐co‐2‐vinyl‐4,6‐diamino‐1,3,5‐triazine) (PS‐co‐VDAT) copolymers were synthesized via conventional free‐radical polymerizations. The polymer structures were confirmed by Fourier transform infrared, NMR, and elemental analysis. The molecular weights were determined by gel permeation chromatography studies, and the thermal properties were characterized by differential scanning calorimetry and thermogravimetric analysis. After treatment with chlorine bleach, PVDAT and PS‐co‐VDAT provided potent antimicrobial functions against multidrug‐resistant Gram‐negative and Gram‐positive bacteria. The antimicrobial functions were durable for longer than 3 months and rechargeable for more than 50 times. The structure–property relationship of the polymers was further discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4089–4098, 2005     

Preparation of block copolymers via Diels Alder reaction of maleimide‐ and anthracene‐end functionalized polymers

A number of diblock copolymers were successfully prepared by Diels–Alder reaction, between maleimide‐ and anthracene‐end functionalized poly (methyl methacrylate) (PMMA), polystyrene (PS), poly(tert‐butyl acrylate) (PtBA), and poly(ethylene glycol) (PEG) in toluene, at 110 °C. For this purpose, 2‐bromo‐2‐methyl‐propionic acid 2‐(3,5‐dioxo‐10‐oxa‐4‐azatricyclo[5.2.1.02,6]dec‐8‐en‐4‐yl)‐ethyl ester, 2 , 9‐anthyrylmethyl 2‐bromo‐2‐methyl propanoate, 3 , and 2‐bromo‐propionic acid 2‐(3,5‐dioxo‐10‐oxa‐4‐azatricyclo[5.2.1.02,6]dec‐8‐en‐4‐yl)‐ethyl ester, 4 , were used as initiators in atom transfer radical polymerization, in the presence of Cu(I) salt and pentamethyldiethylenetriamine (PMDETA), at various temperatures. On the other hand, PEG with maleimide‐ or anthracene‐end functionality was achieved by esterification between monohydroxy PEG and succinic acid monoathracen‐9‐ylmethyl ester, 1 , or 4‐maleimido‐benzoyl chloride. Thus‐obtained PMMA‐b‐PS, PEG‐b‐PS, PtBA‐b‐PS, and PMMA‐b‐PEG block copolymers were characterized by ¹H NMR, UV, and GPC. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1667–1675, 2006     

Foaming behavior of polypropylene/polystyrene blends enhanced by improved interfacial compatibility

A series of polypropylene (PP)/polystyrene (PS) blends were prepared by solvent blending with PS‐grafted PP copolymers (PP‐g‐PS) having different PS graft chain length as compatibilizers. The interfacial compatibility was significantly improved with increasing PS graft chain length until the interface was saturated at PS graft chain length being 3.29 × 10³ g/mol. The blends were foamed by using pressure‐quenching process and supercritical CO₂ as the blowing agent. The cell preferentially formed at compatibilized interface because of low energy barrier for nucleation. Combining with the increased interfacial area, the compatibilized interface lead to the foams with increased cell density compared to the uncompatibilized one. The increase in interfacial compatibility also decreased the escape of gas, held more gas for cell growth, and facilitated the increase in expansion ratio of PP/PS blend foams. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1641–1651, 2008     

Preparation of microcellular polypropylene/polystyrene blend foams with tunable cell structure

By using supercritical carbon dioxide (sc‐CO₂) as the physical foaming agent, microcellular foaming was carried out in a batch process from a wide range of immiscible polypropylene/polystyrene (PP/PS) blends with 10–70 wt% PS. The blends were prepared via melt processing in a twin‐screw extruder. The cell structure, cell size, and cell density of foamed PP/PS blends were investigated and explained by combining the blend phase morphology and morphological parameters with the foaming principle. It was demonstrated that all PP/PS blends exhibit much dramatically improved foamability than the PP, and significantly decreased cell size and obviously increased cell density than the PS. Moreover, the cell structure can be tunable via changing the blend composition. Foamed PP/PS blends with up to 30 wt% PS exhibit a closed‐cell structure. Among them, foamed PP/PS 90:10 and 80:20 blends have very small mean cell diameter (0.4 and 0.7 µm) and high cell density (8.3 × 10¹¹ and 6.4 × 10¹¹ cells/cm³). Both of blends exhibit nonuniform cell structure, in which most of small cells spread as “a string of beads.” Foamed PP/PS 70:30 blend shows the most uniform cell structure. Increase in the PS content to 50 wt% and especially 70 wt% transforms it to an irregular open‐cell structure. The cell structure of foamed PP/PS blends is strongly related to the blend phase morphology and the solubility of CO₂ in PP more than that in PS, which makes the PP serve as a CO₂ reservoir. Copyright © 2009 John Wiley & Sons, Ltd.     

Polymethylene‐b‐polystyrene diblock copolymer: Synthesis,property, and application

The design and synthesis of well‐defined polymethylene‐b‐polystyrene (PM‐b‐PS, M_n = 1.3 × 10⁴–3.0 × 10⁴ g/mol; M_w/M_n (GPC) = 1.08–1.18) diblock copolymers by the combination of living polymerization of ylides and atom transfer radical polymerization (ATRP) was successfully achieved. The ¹H NMR spectrum and GPC traces of PM‐b‐PS indicated the successful extension of PS segment on the PM macroinitiator. The micellization behavior of such diblock copolymers in tetrahydrofuran were characterized by dynamic light scattering (DLS) and atomic force microscopy (AFM) techniques. The average aggregate sizes of PM‐b‐PS diblock copolymers with the same length of PM segment in tetrahydrofuran solution (1.0 mg mL^?1) increases from 104.2 nm to 167.7 nm when the molecular weight of PS segment increases. The spherical precipitated aggregates of PM‐b‐PS diblock copolymers with an average diameter of 600 nm were observed by AFM. Honeycomb porous films with the average diameter of 3.0 μm and 6.0 μm, respectively, were successfully fabricated using the solution of PM‐b‐PS diblock copolymers in carbon disulfide via the breath‐figure (BF) method under a static humid condition. The cross‐sections of low density polyethylene (LDPE)/polystyrene (PS)/PM‐b‐PS and LDPE/polycarbonate (PC)/PM‐b‐PS blends were observed by scanning electron microscope and reveal that the PM‐b‐PS diblock copolymers are effective compatilizers for LDPE/PS and LDPE/PC blends. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1894–1900, 2010     

Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C5Me5TiMe3/B(C6F5)3/Al(oct)3 catalyst

This article reports a new methodology for preparing highly stereoregular styrene (ST)/1,3‐butadiene (BD) block copolymers, composed of syndiotactic polystyrene (syn‐PS) segments chemically bonded with cis‐polybutadiene (cis‐PB) segments, through a stereospecific sequential block copolymerization of ST with BD in the presence of a C₅Me₅TiMe₃/B(C₆F₅)₃/Al(oct)₃ catalyst. The first polymerization step, conducted in toluene at ?25 °C, was attributed to the syndiospecific living polymerization of ST. The second step, conducted at ?40 °C, was attributed to the cis‐specific living polymerization of BD. The livingness of the whole polymerization system was confirmed through a linear increase in the weight‐average molecular weights of the copolymers versus the polymer yields in both steps, whereas the molar mass distributions remained constant. The profound cross reactivity of the styrenic‐end‐group active species with BD toward ST led to the production of syn‐PS‐b‐cis‐PB copolymers with extremely high block efficiencies. Because of the presence of crystallizable syn‐PS segments, this copolymer exhibited high melting temperatures (up to 270 °C), which were remarkably different from those of the corresponding anionic ST–BD copolymers, for which no melting temperatures were observed. Scanning electron microscopy pictures of a binary syn‐PS/cis‐PB blend with or without the addition of the syn‐PS‐b‐cis‐PB copolymers proved that it could be used as an effective compatibilizer for noncompatibilized syn‐PS/cis‐PB binary blends. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1188–1195, 2005     

Facile Synthesis of N‐(Benzyl‐1H‐1,2,3‐Triazol‐5‐yl) Methyl)‐4‐(6‐Methoxybenzo [d] Thiazol‐2‐yl)‐2‐Nitrobenzamides via Click Chemistry

A series of novel N‐((l‐benzyl‐lH‐l,2,3‐triazol‐5‐yl) methyl)‐4‐(6‐methoxy benzo[d ]thiazol‐2‐yl)‐2‐nitrobenzamide derivatives were prepared from 4‐(6‐methoxybenzo[d ]thiazol‐2‐yl)‐2‐nitro‐N‐(prop‐2‐ynyl) benzamide with benzyl azides by using click reaction (copper‐catalyzed Huisgen 1,3‐dipolar cycloaddition reaction) in the presence of CuSO₄.5H₂O and sodium ascaorbate. All the newly synthesized compounds were evaluated further in vitro antimicrobial activity against Gram‐positive bacteria (Staphylococcus aureus and Bacillus subtillis ), Gram‐negative bacteria (Echerichia coli and Pseudomonas aeuroginosa ), and fungi (Aspergillus niger and Aspergillusfumigatus ) strains. The new compounds were characterized based on spectroscopic evidence. Among them compounds 10a , 10h , and 10i were showed promising activity when compared with standard drugs Ciprofloxacin and Miconazole.