bluuebunny/crossref_metadata_2025_split huggingface dataset:
UV Assisted Surface Modification of Polystyrene in the Presence of Trialkylsilanes
Authors: Spanring Julia , Buchgraber Christian , Ebel Maria F. , Svagera R. , Kern Wolfgang 
Published: November 2005

AbstractSummary: A process for the photochemical modification of polystyrene (PS) surfaces employing organosilane compounds has been developed. Polystyrene was irradiated in presence of trialkylsilanes [ethyldimethylsilane (EDMS), trimethylsilane (TrMS)]. UV irradiation was carried out with a medium pressure (MP) Hg lamp and a 193 nm ArF* excimer laser. FT‐IR and X‐ray photoelectron spectroscopy (XPS) evidenced that after irradiation alkylsilyl groups were covalently bond to the polymer surface. Contact angle measurements proved a significant lowering in surface energy of polystyrene as a result of the photomodification process. When EDMS was used as photoreactive reagent, the introduction of SiH groups onto the polymer surface was also found. The introduction of SiH bonds onto polymer surfaces provides new possibilities for further surface functionalization. Atomic force microscopy (AFM) showed that Hg lamp irradiation does not exert significant changes in surface topography, while 193 nm excimer laser irradiation leads to surface corrugation. Summing up, it is demonstrated that organosilanes can be employed in UV reactions to attach silyl and also SiH groups onto polystyrene surfaces. Possible reaction mechanisms are discussed.
magnified image
Miscibility Enhancement on the Immiscible Binary Blend of Poly(vinyl phenol) and Poly(acetoxystyrene) with Poly(ethylene oxide)
Authors: Kuo Shiao‐Wei , Liu Wen‐Pin , Chang Feng‐Chih 
Published: November 2005

AbstractSummary: The miscibility and hydrogen‐bonding behaviors of ternary polymer blends of poly(ethylene oxide) (PEO)/poly(vinyl phenol) (PVPh)/poly(acetoxystyrene) (PAS) were investigated by using DSC and Fourier transform infrared spectroscopy (FTIR). The PEO is miscible with both PVPh and PAS based on the observed single Tg over the entire composition range. FTIR was used to study the hydrogen‐bonding interactions between PEO with PAS and PVPh, respectively. Quantitative analyses show that the strength of hydrogen‐bonding strength is of the order of the hydroxyl‐ether inter‐association of PVPh/PEO blend > the hydroxyl‐hydroxyl self‐association of pure PVPh > the hydroxyl‐carbonyl inter‐association PVPh/PAS blend at room temperature. Furthermore, the addition of PEO is able to enhance the miscibility of immiscible PVPh/PAS binary blends at lower (20 wt.‐%) or higher (60 and 80 wt.‐%) PEO content. However, there exists a closed immiscibility loop in the phase diagram at 40 wt.‐% PEO content due to the “Δχ” and “ΔK” effects in this hydrogen‐bonded ternary polymer system. Therefore, an interesting and unusual sandwich phase diagram has been observed in this ternary polymer blend.Ternary phase diagram of the PEO/PAS/PVPh system.magnified imageTernary phase diagram of the PEO/PAS/PVPh system.
Propylene Polymerization Using ansa‐Zirconocenes with Water/Pentafluorophenol‐Modified Methylaluminoxane
Authors: Fujita Masayuki , Seki Yoshinori , Miyatake Tatsuya 
Published: November 2005

AbstractSummary: We have confirmed that water‐ and pentafluorophenol‐modified isobutylmethylaluminoxane (W/PM‐MMAO) enhances the productivity and stereoregularity of the yielded polymer and increases its molecular weight when propylene is polymerized using C2‐symmetric ansa‐zirconocenes. 13C NMR analysis shows that when W/PM‐MMAO is used as a cocatalyst with C2‐symmetric ansa‐zirconocenes, although the pentad peaks of the stereoerrors derived from enantiofacial misinsertion have still existed; those derived from the epimerization of the growing chain end that occurred with β‐hydride elimination disappear. Therefore, we propose that W/PM‐MMAO interacts more strongly to the cationic metal center of metallocene than does MMAO owing to steric and electronic effect, and W/PM‐MMAO suppresses β‐hydride elimination, resulting in the production of polypropylene with higher molecular weight and isotacticity. To the contrary, there was no significant difference in the structure of the yielded polymer when W/PM‐MMAO was used with Cs‐symmetric ansa‐zirconocenes. In the case of Cs‐symmetric ansa‐zirconocene, the stereoerror is mostly the result of monomer insertion error, and small amount of stereoerror caused by “skipped” insertion, not from the epimerization of the polymer chain end that occurs after β‐hydride elimination; therefore, there might not be any difference of the microstructure of yielded polymers between MMAO and W/PM‐MMAO. It can be concluded that the both cases of C2‐ and Cs‐symmetric ansa‐zirconocenes are used as a catalyst, and water and phenol modification of MMAO does not affect the monomer misinsertion which is one of the mechanisms of the stereoerrors.13C NMR spectra of isotactic PP. (a) Sample 1. (b) Sample 2.magnified image13C NMR spectra of isotactic PP. (a) Sample 1. (b) Sample 2.
Core–Shell–Corona Micellar Complexes between Poly(ethylene glycol)‐block‐poly(4‐vinyl pyridine) and Polystyrene‐block‐poly(acrylic acid)
Authors: Zhang Wangqing , Shi Linqi , Miao Z.‐J. , Wu Kai , An Yingli 
Published: November 2005

AbstractSummary: The complexation between polystyrene‐block‐poly(acrylic acid) (PS‐b‐PAA) micelles and poly(ethylene glycol)‐block‐poly(4‐vinyl pyridine) (PEG‐b‐P4VP) is studied and a facile strategy is proposed to prepare three‐layered core–shell–corona micellar complexes. Micellization of PS‐b‐PAA in ethanol gives rise to spherical core–shell micelles with the PS block as the core and the PAA block as the shell. When PEG‐b‐P4VP is added into the core–shell micellar solution, the P4VP block penetrates into the PAA shell and is absorbed into the core–shell micelles to form spherical core–shell–corona micellar complexes with the PS block as the core, the bonded PAA/P4VP blocks as the shell, and the PEG block as the corona. The core radius, Rc, of the core–shell–corona micellar complexes, 15.1 nm, is equal to that of the core–shell micelles, and the thickness, Ds, of the PEG corona is about 1.5 nm, while the shell thickness, Ds, ranges from 12.2 to 15.7 nm depending on the weight ratio of PEG‐b‐P4VP to PS‐b‐PAA.Schematic formation of core–shell–corona micellar complexes.magnified imageSchematic formation of core–shell–corona micellar complexes.
Photorheology of Fast UV‐Curing Multifunctional Acrylates
Authors: Schmidt Lars E. , Leterrier Yves , Vesin Jean‐Marc , Wilhelm Manfred , Månson Jan‐Anders E. 
Published: November 2005

AbstractSummary: The fast photopolymerization of different multifunctional acrylates was analyzed by means of photorheology. The materials studied included a penta/hexaacrylate monomer and two different acrylated hyperbranched polymers. The sensitivity of the commercial rheometer was improved several‐fold, by a combination of an adaptive filter algorithm and improved data treatment, using powerful oversampling acquisition hardware. The novel set‐up was capable of monitoring up to a five orders of magnitude increase in shear modulus within short experiment timescales (about 10 s). The improvement in sensitivity and acquisition rate enabled the induction time, gelation, and vitrification of the multifunctional acrylates to be determined. In addition, the influence of UV intensity on stiffness build‐up within these materials was studied. In the case of the penta/hexaacrylate system, gelation and vitrification were detected as distinct events, in contrast to the second‐generation hyperbranched polyester, for which vitrification could not be identified. These findings are related to the difference in the glass transition temperature of the cured networks.Absolute value of the complex shear modulus as a function of time for different acrylate monomers during UV curing.imageAbsolute value of the complex shear modulus as a function of time for different acrylate monomers during UV curing.
Lazard's Theorem forS‐posets
Authors: Bulman‐Fleming Sydney , Laan Valdis 
Published: November 2005

AbstractIn 1971, inspired by the work of Lazard and Govorov for modules over a ring, Stenström proved that the strongly flat right actsASover a monoidS(that is, the acts that are directed colimits of finitely generated free acts) are those for which the functorAS⊗ (from the category of leftS‐acts into the category of sets) preserves pullbacks and equalizers. He also provided interpolation‐type conditions (now referred to in the literature as Property (P) and Property (E)) characterizing strong flatness. Unlike the situation for modules over a ring, strong flatness is strictly stronger than (mono‐) flatness (wherein the functorAS⊗ is required only to preserve monomorphisms). The study of flatness properties of partially ordered monoids acting on partially ordered sets was initiated by S. M. Fakhruddin in the 1980s, and has been continued recently in the paper “Indecomposable, projective, and flatS‐posets” by Shi, Liu, Wang, and Bulman–Fleming, Comm. Algebra33, 235–251 (2005). In that paper, a criterion for the equality of elements in a tensor product ofS‐posets is given and a version of Property (P) is presented that, as in the unordered case, implies flatness and is implied by projectivity. The present paper introduces a corresponding Property (E) and establishes an analogue of the Lazard–Govorov–Stenström theorem in the context ofS‐posets. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pointwise estimates for Green's kernel of a mixed boundary value problem to the Stokes system in a polyhedral cone
Authors: Maz'ya V. , Rossmann J. 
Published: November 2005

AbstractThe paper deals with a mixed boundary value problem for the Stokes system in a polyhedral cone. Here different boundary conditions (in particular, Dirichlet, Neumann, free surface conditions) are prescribed on the sides of the polyhedron. The authors obtain regularity results for weak solutions in weighted L 2 Sobolev spaces and prove point estimates of Green's matrix. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On a class of quasilinear eigenvalue problems in RN
Authors: Kristály Alexandru , Varga Csaba 
Published: November 2005

AbstractWe study an eigenvalue problem in RN which involves the p ‐Laplacian (p > N ≥ 2) and the nonlinear term has a global (p – 1)‐sublinear growth. The existence of certain open intervals of eigenvalues is guaranteed for which the eigenvalue problem has two nonzero, radially symmetric solutions. Some stability properties of solutions with respect to the eigenvalues are also obtained. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A New Approach to Thick Films of a Block Copolymer with Ordered Surface Structures
Authors: Han Xia , Xu Jian , Liu Honglai , Hu Ying 
Published: November 2005

AbstractSummary: A unique and simple method to prepare films with various ordered nanoscopic cylindrical patterns on the surface is reported. Various solutions of gemini surfactants with different spacers were used as a nanotemplate, on which thick polymer films were fabricated by the supramolecular assembly of a native or chemically modified polystyrene‐block‐poly(ethylene/butylene)‐block‐polystyrene (SEBS) triblock copolymer. At the air/polymer surface, normal oriented cylindrical nanodomains formed by poly(ethylene/butylene) (PEB) block associates surrounded by polystyrene (PS) blocks are exhibited. While at the polymer/surfactant solution interface, parallel cylindrical nanodomains formed by PEB block stripes alternating with PS block stripes are observed. The ordered structure of the surface can be adjusted by changing the surfactant and the chemical nature of the polymer. In a special case using Gemini 16‐1‐Ph‐1‐16 and SEBS chemically modified with 2 wt.‐% maleic anhydride, a nearly perfect hexagonal ordered structure is obtained.The AFM micrograph and associated FFT (inset) of the morphology of a SEBS thick film formed on a 16‐1‐Ph‐1‐16 solution to give a nearly perfect hexagonal ordered structure.magnified imageThe AFM micrograph and associated FFT (inset) of the morphology of a SEBS thick film formed on a 16‐1‐Ph‐1‐16 solution to give a nearly perfect hexagonal ordered structure.
Super‐Hydrophobic PDMS Surface with Ultra‐Low Adhesive Force
Authors: Jin Meihua , Feng Xinjian , Xi Jinming , Zhai Jin , Cho Kilwon , Feng Lin , Jiang Lei 
Published: November 2005

AbstractSummary: Rough polydimethylsiloxane (PDMS) surface containing micro‐, submicro‐ and nano‐composite structures was fabricated using a facile one‐step laser etching method. Such surface shows a super‐hydrophobic character with contact angle higher than 160° and sliding angle lower than 5°, i.e. self‐cleaning effect like lotus leaf. The wettabilities of the rough PDMS surfaces can be tunable by simply controlling the size of etched microstructures. The adhesive force between etched PDMS surface and water droplet is evaluated, and the structure effect is deduced by comparing it with those own a single nano‐ or micro‐scale structures. This super‐hydrophobic PDMS surface can be widely applied to many areas such as liquid transportation without loss, and micro‐pump (creating pushing‐force) needless micro‐fluidic devices.Etched PDMS surface containing micro‐, submicro‐, and nano‐composite structures shows a self‐cleaning effect with water CA as high as 162° and SA lower than 5°.magnified imageEtched PDMS surface containing micro‐, submicro‐, and nano‐composite structures shows a self‐cleaning effect with water CA as high as 162° and SA lower than 5°.
Thermoswitchable Electronic Properties of a Gold Nanoparticle/Hydrogel Composite
Authors: Zhao Xiuli , Ding Xiaobin , Deng Zhenghua , Zheng Zhaohui , Peng Yuxing , Long Xinping 
Published: November 2005

AbstractSummary: A well‐dispersed gold nanoparticle/poly(N‐isopropylacrylamide) (PNIPAm) hydrogel nanocomposite with thermoswitchable electrical properties is prepared by the copolymerization of functional Au nanoparticles with N‐isopropylacrylamide. It is found that the electrical conductivity of the nanocomposite changes by two orders of magnitude at moderate temperature (Ttran) upon temperature stimuli. The change of electrical properties is reversible during a heating and cooling cycle.Schematic illustration of the mechanism of the thermo‐switchable electronic properties of the Au nanoparticle/PNIPAm composite.magnified imageSchematic illustration of the mechanism of the thermo‐switchable electronic properties of the Au nanoparticle/PNIPAm composite.
Low‐Temperature Growth of Thick Polystyrene Brushes via ATRP
Authors: Samadi Azadeh , Husson Scott M. , Liu Yong , Luzinov Igor , Michael Kilbey S. 
Published: November 2005

AbstractSummary: This contribution describes the graft polymerization of polystyrene (PS) by atom transfer radical polymerization at 50, 60, and 75 °C. Thick PS brushes were grown from initiator‐functionalized PGMA layers on silicon, and constant growth rates provide indirect evidence that the polymerizations were controlled.Formation of polystyrene brushes at T < Tg by ATRP of styrene from α‐bromoester initiator‐functionalized poly(glycidyl methacrylate) layers.magnified imageFormation of polystyrene brushes at T < Tg by ATRP of styrene from α‐bromoester initiator‐functionalized poly(glycidyl methacrylate) layers.
Automated protein identification by tandem mass spectrometry: Issues and strategies
Authors: Hernandez Patricia , Müller Markus , Appel Ron D. 
Published: November 2005

AbstractProtein identification by tandem mass spectrometry (MS/MS) is key to most proteomics projects and has been widely explored in bioinformatics research. Obtaining good and trustful identification results has important implications for biological and clinical work. Although well matured, automated software identification of proteins from MS/MS data still faces a number of obstacles due to the complexity of the proteome or procedural issues of mass spectrometry data acquisition. Expected or unexpected modifications of the peptide sequences, polymorphisms, errors in databases, missed or non‐specific cleavages, unusual fragmentation patterns, and single MS/MS spectra of multiple peptides of the same m/z are so many pitfalls for identification algorithms. A lot of research work has been carried out in recent years that yielded new strategies to handle a number of these issues. Multiple MS/MS identification algorithms are now available or have been theoretically described. The difficulty resides in choosing the most adapted method for each type of spectra being identified. This review presents an overview of the state‐of‐the‐art bioinformatics approaches to the identification of proteins by MS/MS to help the reader doing the spadework of finding the right tools among the many possibilities offered. © 2005 Wiley Periodicals, Inc. Mass Spec Rev 25:235–254, 2006
Controlled Radical Polymerization of N‐Vinylpyrrolidone by Reversible Addition‐Fragmentation Chain Transfer Process
Authors: Devasia Renjith , Bindu Raveendra L. , Borsali Redouane , Mougin Nathalie , Gnanou Yves 
Published: November 2005

AbstractSummary: Poly(N‐vinylpyrrolidone) (PNVP) was polymerized by RAFT process using diphenyldithiocarbamate of diethylmalonate (DPCM) as the reversible chain transfer agent in the presence of a small percentage of a conventional radical initiator (AIBN). The molar mass of the polymers synthesized by this method was found to increase with conversion and time. The presence of end group in the polymer chain could be confirmed by 1H NMR spectra. The molar masses calculated using 1H NMR spectroscopy and static light scattering (SLS) showed good agreement with the theoretical molar masses. The RAFT compound was fully consumed during the initial stages of the polymerization itself. The controlled nature of these polymers was further confirmed by generating diblock copolymers by sequential addition of monomers such as styrene or n‐butyl acrylate (n‐BA). PNVP efficiently participated as a macro‐RAFT reagent, and cross‐over reaction between the two blocks efficiently occurred. The successful diblock copolymer synthesis using PNVP as macro‐transfer reagent further confirms the “controlled” nature of such synthetic procedure.
Dynamics of Biological Polyelectrolytes
Authors: Pecora R. 
Published: November 2005

AbstractSummary: Biological polymers and structures, including proteins and DNAs, can be made in essentially monodisperse form. Proteins usually have well‐defined shapes. Duplex oligonucleotides are rigid and rodlike, and longer DNAs are semiflexible coils. The DNAs also constitute a homologous series. The dynamics of both proteins and DNAs can be studied by readily available techniques such as dynamic light scattering (DLS) and fluorescence correlation spectroscopy (FCS). These systems can thus be used as model systems to elucidate elusive charge effects on the dynamics of macromolecules in solution (polyelectrolyte effects) for both rigid and semiflexible polymers. We present here as examples the results of measurements of mutual and self‐diffusion coefficients dynamics of a rodlike oligonucleotide as functions of polymer concentration and the concentration of added salt (which screens the charges).
Hydroxy and Di‐Hydroxy End‐Capped Polybutadiene as Reactive Steric Stabilizers for the Synthesis of Polyurethane Particles in Organic Dispersant Media
Authors: Radhakrishnan Bindushree , Balerdi Goretti , Cloutet Eric , Cramail Henri 
Published: November 2005

AbstractSummary: The synthesis of polyurethane particles by polyaddition of ethylene glycol (EG) and tolylene‐2,4‐diisocyanate (TDI) in cyclohexane at 60 °C was investigated in the presence of ω‐hydroxy and ω,ω′‐dihydroxy polybutadiene, used as reactive steric stabilizers. The effect of the functionality and concentration of the reactive polybutadiene, as well as the monomer addition procedure, onto the polyurethane particle formation was studied. Calibrated PUR particles with an average diameter in the range 1–2 µm could be readily obtained.
Microstructures Based on Thermotropic Liquid‐Crystalline Polymers in the Low Molar Mass Nematogenic 5CB
Authors: Pereira Fabiano V. , Zandoná Rodrigo , Borsali Redouane , Merlo Aloir A. , da Silveira Nadya P. 
Published: November 2005

AbstractSummary: The unique characteristics of two polyacrylates having the same side chain chiral mesogenics groups and different spacer lengths allowed the stabilization of ordered polymer rich‐phases in solution with the nematic solvent 5CB. These microstructures are smectic having fibrous‐like and rode‐like morphologies, in spite of the mesophases of the polymers in bulk. The interactions between the mesogenic groups in the polymer and the solvent 5CB stabilize the microstructures and leads to birefringence at temperatures above the 5CB clearing point. Polarized optical microscopy data are complemented by SAXS to fully describe the mesomorphic behavior of the mixtures.
Tailoring the Flow Properties of Soft Colloidal Dispersions
Authors: Cloitre Michel 
Published: November 2005

AbstractSummary: The dynamics and the non‐linear rheology of concentrated dispersions of soft particles are shown to exhibit generic properties. They display both solid‐like and liquid‐like properties depending on the applied stress. Below the yield point, dispersions exhibit history‐dependent phenomena that have all the hallmarks of ageing in glasses. The close‐packed disordered structures of the dispersions lie at the heart of this behaviour. Other properties such as the propensity of pastes to slip on solid surfaces appear to be governed by specific contact interactions between the squeezed particles.
Soy Protein Isolate Based Films: Influence of Sodium Dodecyl Sulfate and Polycaprolactone‐triol on Their Properties
Authors: Schmidt Vanessa , Giacomelli Cristiano , Soldi Marly S. , Soldi Valdir 
Published: November 2005

AbstractSummary: We report on the preparation and properties of soy protein isolate (SPI)‐sodium dodecyl sulfate (SDS)‐polycaprolactone‐triol (PCL‐T) films obtained by solvent casting from solutions containing variable amounts of SDS or SDS/PCL‐T. It is shown that the mechanical and thermal properties, and the morphology of SPI‐based biofilms can be easily controlled by changing SDS, PCL‐T, and moisture contents, enabling the fabrication of rigid and flexible materials as pure SPI films [Young's modulus ∼ 1 400 MPa, elongation at break (E) ∼ 2%, and glass transition temperature (Tg) ∼ 150 °C] and SPI/SDS/PCL‐T films with [PCL‐T] ≥ 18% (Young's modulus ∼ 50 MPa, E ∼ 90%, and Tg ∼ 135 °C), respectively. Micrographs taken at the cross‐section of biofilms whose [PCL‐T] ≥ 18% revealed the occurrence of a porous matrix, whereas a dense bulk phase was otherwise observed (pure SPI, SPI/SDS, and SPI/SDS/PCL‐T films with [PCL‐T] < 18%).
Conducting Polymer‐Based Chemiresistive Sensor for Organic Vapours
Authors: Rosa Roberta M. , Szulc Ricardo L. , Li Rosamaria W. C. , Gruber Jonas 
Published: November 2005

AbstractSummary:Poly(2‐bromo‐5‐hexyloxy‐p‐phenylenevinylene), BHPPV, was electrochemically synthesized in 81% yield. The polymer presented high solubility in organic solvents, in spite of its relatively high molar weight ($\overline{M}_{\rm w}$ = 80 000), and showed to be thermally resistant up to 130 °C. Gas sensors made from thin films of CSA doped BHPPV, deposited on interdigitated electrodes, responded to five different solvents. Plots of relative response versus relative recovery showed good discrimination of the five solvents.