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Months following the traumatic termination of my analysis I engaged in self-analytic work in which I was able to rework the events of the termination and their significance in terms of my history. Fundamental differences between my self-analytic process and that of my formal analysis led me to consider how termination may affect the ensuing self-analytic process. In this paper, I look at aspects of termination that have to do with the dissolution of symbiotic ties with the analyst; I will try to show that relinquishment of the frame provides an impetus both for consolidation and reworking of an identification with the analyst, which may enable the analysand to develop a personal way of thinking about the unconscious that differs from that of the analyst. I further suggest that there are inevitable limitations to the analytic process which manifest in the development of irreducible bastions, and that the dissolution of the frame at termination provides an opportunity for self-analytic resolution of those bastions which may allow self-understanding beyond what could have been attained within the formal analytic setting. Finally, I offer some speculations on how these processes may have played out between Freud and Fliess in Freud's self-analysis. [ABSTRACT FROM AUTHOR]

The literature data concerning features of the kinetics and mechanisms of elementary steps of liquid-phase oxidation of cyclohexane and its oxygen derivatives are considered and analyzed. A comparison of rates of intermolecular and intramolecular reactions of cyclohexylperoxyl radicals under the industrial conditions indicated a necessity to take into account intramolecular interactions. The occurrence of cross recombination of hydroperoxyl and α-hydroxyperoxyl radicals without chain termination in the course of cyclohexanol and 2-hydroxycyclohexanol oxidation was proved. A significance of degenerate branching reactions involving cyclohexyl hydroperoxide in the industrial process of cyclohexane oxidation at 423 K was evaluated. The influence of the electron-withdrawing functional groups on the reactivity of carbon-hydrogen bonds of organic compounds in the reactions with electrophilic peroxyl radicals was studied. The low conversion of a substrate in the industrial process are mainly caused by the radicalchain oxidation of cyclohexanone leading only to by-products. The catalysts of cyclohexane oxidation, viz., compounds of variable valence metals, affect the reaction rate and ratio of the yields of the target products (cyclohexyl hydroperoxide, cyclohexanol, and cyclohexanone) but exert no effect on their relative reactivity. The use of the catalytic additives increasing the yield of cyclohexanone in the step of cyclohexane oxidation in the production of caprolactam is revealed to be inexpedient. [ABSTRACT FROM AUTHOR]

Abstract: The model and methodology for estimating diffusion‐controlled rate coefficients for the methyl methacrylate polymerization system reported in Parts I and II of this series is extended to include the chain transfer reaction to an agent (CTA). Theoretical and experimental results exhibit minima in the rate of polymerization curves at low conversions as it is observed in the absence of CTA. Such minima are proposed to be the onset of the autoacceleration effect where the termination reaction undergoes a transition from chemically controlled to diffusion controlled where the segmental mobility of the chain ends plays a key role. As the CTA concentration increases, the conversion at which the minimum is presented is higher and the autoacceleration is less pronounced. This behavior is explained in terms of the effect of polymer chain entanglements and segmental mobility of the chain ends on the termination rate coefficient kt. [ABSTRACT FROM AUTHOR]

The high-temperature superconductor (HTS) CrossConductor (HTS CroCo) is a modified stacked-tape arrangement, aiming for high current density and easy long-length fabrication. It is intended to be used as a strand for a high current cable in industrial dc applications or large high-field magnets. In order to allow for an economical operation, terminations, joints, and connector parts need to be sufficiently low-resistive to minimize the heat generation and thus the cooling cost. On the other hand, industrial applicability requires reliable and easy-to-use concepts. In this paper, three approaches to fabricate soldered joints and terminations for HTS CroCos are presented and assessed based on resistance measurements at 77 K, self-field. Termination resistances of some tens of nano-Ohms were achieved for the best termination concepts. Additionally, four types of low-resistive  HTS CroCo connectors with bending radii of less than 5 cm are introduced and assessed. For the best connector types, some tens of nano-Ohms were achieved giving rise to a heat generation of less than 1 W at operating conditions. [ABSTRACT FROM PUBLISHER]

Two 2-chloromagnesiothiophenes having the methoxy group at the 3- and 4-position were applied for the termination reaction of living poly(3-hexylthiophene) (P3HT). The number-averaged molecular weights of obtained P3HT approximately agreed with the theoretical value, and the high regioregularity of polymers were confirmed. The comparison of the 1 H NMR spectra of P3HT with those of model compounds in addition to the analysis of the MALDI-TOF mass spectra suggested the incorporation of the methoxythiophene unit. The termination reaction using 2-chloromagnesio-3-methoxythiophene ( GT1 ) and 2-chloromagnesio-4-methoxythiophene ( GT2 ) resulted in P3HT with the non-uniform terminal structure and that having the terminating unit at both chain ends, respectively. These facts can be ascribed to the efficiency of the elementary process (transmetallation, reductive elimination, reverse chain walking, and oxidative addition) in the catalytic cycle. On the other hand, 2-chloromagnesio-3-oxazolylthiophene ( GT3 ) exhibited the poor transmetallation activity due to the pronounced steric hindrance. It was found that the addition of LiCl for accelerating the transmetallation step and the coexistence of styrene for trapping the zero-valent nickel complex give P3HT bearing the oxazolylthiophene unit at the propagating end. [ABSTRACT FROM AUTHOR]

A stopped-flow NMR probe is described that enables fast flow rates, short transfer times, and equilibration of the reactant magnetization and temperature prior to reaction. The capabilities of the probe are demonstrated by monitoring the polymerization of lactide as catalyzed by the air-sensitive catalyst 1,3-dimesitylimidazol-2-ylidene (IMes) over the temperature range of −30 to 40 °C. The incorporation of stopped-flow capabilities into an NMR probe permits the rich information content of NMR to be accessed during the first few seconds of a fast reaction. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We study the effect of polydispersity on the structure of polymer brushes by analytical theory, a numerical self-consistent field approach, and Monte Carlo simulations. The polydispersity is represented by the Schulz-Zimm chain-length distribution. We specifically focus on three different polydispersities representing sharp, moderate, and extremely wide chain length distributions and derive explicit analytical expressions for the chain end distributions in these brushes. The results are in very good agreement with numerical data obtained with self-consistent field calculations and Monte Carlo simulations. With increasing polydispersity, the brush density profile changes from convex to concave, and for given average chain length Nn and grafting density σ, the brush height H is found to scale as (H/Hmono - 1) ∝ (Nw/Nn - 1)1/2 over a wide range of polydispersity indices Nw/Nn (here Hmono is the height of the corresponding monodisperse brush). Chain end fluctuations are found to be strongly suppressed already at very small polydispersity. On the basis of this observation, we introduce the concept of the brush as a near-critical system with two parameters (scaling variables), (Nnσ2/3)-1 and (Nw/Nn - 1)1/2, controlling the distance from the critical point. This approach provides a good description of the simulation data. Finally, we study the hydrodynamic penetration length lp for brush-coated surfaces in flow. We find that it generally increases with polydispersity. The scaling behavior crosses over from lp - Nn1/2-1/6 for monodisperse and weakly polydisperse brushes to lp - Nn2/3 for strongly polydisperse brushes. [ABSTRACT FROM AUTHOR]

Sterically hindered rac-dimethylsilylbis(2-methyl-3-propylindenyl)hafnium dimethyl (1) activated with dimethylanilinium tetrakis(perfluoronaphthylborate) (2) gave high levels of allylic chain ends in the oligomerization of higher α-olefins such as 1-octene. Solution oligomerization of 1-octene in hexanes yielded atactic macromers with roughly 60 mol % vinyl termination and lesser amounts of trisubstituted (25%) and vinylidene (20%) termination. To further probe the mechanism of elimination, oligomerization with 1-octene (1-13C) was performed and the label distribution determined by 13C NMR spectroscopy. Enhancement of the methylene (H2CC−) vinyl resonance was observed, supporting β-hexyl elimination as a possible mechanistic step and ruling out allylic formation by a chain-walking mechanism prevalent in late-transition-metal systems. [ABSTRACT FROM AUTHOR]

In the surface-initiated atom transfer radical polymerization, the polymerization proceeds both in solution and on surface. This work reports a modeling study, describing the growth of the molecular weight and polydispersity of polymer both on surface and in solution. It is found that both surface radical termination and solution monomer consumption significantly suppress the growth rate of polymer layer. Besides, the former affects the molecular weights of polymer both on surface and in solution. If the termination rate constant in solution ( kt,sol -sol) is the same as that of surface and solution interfaces ( kt,sol -surf), and the surface termination ( kt,surf -surf) is negligible, then the polymers both on surface and in solution have the same molecular weight. However, if surface radicals terminate among themselves, the molecular weight of polymer on surface will lower than that in solution. Such termination is promoted by surface radical migration through activation/deactivation reactions in solution. When kt,sol -surf < kt,sol -sol, the molecular weight of surface polymer becomes higher than that in solution. This situation is resulted from surface radical trap due to a high grafting density. [ABSTRACT FROM AUTHOR]

The laser single pulse (SP)-pulsed laser polymerization (PLP)-electron paramagnetic resonance (EPR) technique allows for deducing propagation (kp) and termination (kt) rate coefficients, including the chain-length dependence of kt, from a single pulsed-laser experiment. The method, which is particularly well suited for slowly terminating radicals, e.g., sterically hindered and ionic radicals, is illustrated for di(n-butyl) itaconate in bulk at temperatures from 30 to 60 °C. The time evolution of the DBI radical concentration is measured with a high time resolution at constant magnetic field. Propagation is associated with a relatively low pre-exponential A(kp), which is responsible for the small kp value of 6.8 L mol-1 s-1 at 30 °C. The chain-length dependence (CLD) of kt, deduced from the same SP-PLP-EPR signal as is kp, turns out to be adequately represented by the composite model. Whereas typical numbers are found for the power-law exponents for short and long radicals and for the crossover chain length, the parameter kt(1,1), which represents mutual termination of two radicals of chain length unity, is by 2 orders of magnitude below kt(1,1) of monomers without significant steric hindrance. [ABSTRACT FROM AUTHOR]

Interface characteristics of Co 2 MnSi/Ag/Co 2 MnSi trilayer have been investigated by means of first-principles. The most likely interface is formed by connecting MnSi-termination to the bridge site between two Ag atoms. As annealed at high temperature, the formation of interface DO 3 disorder is most energetically favorable. The spin polarization is reduced by both the interface itself and interface disorder due to the interface state occurs in the minority-spin gap. As a result, the magneto-resistance ratio has a sharp drop based on the estimation of a simplified modeling. [ABSTRACT FROM AUTHOR]

A first-principles study, using a linear-response approach based on the pseudopotential method and the generalised gradient approximation, has been made to examine the phonon spectrum of the hydrogen-terminated Si(110)-(1 × 1) surface. The calculated results compare very well with the results determined from a recent high-resolution electron-energy-loss spectroscopy measurement. In particular, the energy locations and polarization characteristics of the H Si bond bending and H Si stretching surface phonon modes have been determined and discussed in detail. The zone-centre splitting of the two H Si stretching surface phonon modes is found to be 2.4 meV, which compares very well with the experimental value of 1.9 meV. [ABSTRACT FROM AUTHOR]

Surfactant mediated growth of Ge layers and formation of small Ge clusters on Si(111) are promising assemblage processes with envisioned applications in areas such as nanoelectronics or photovoltaics. They critically depend on migration of Si and Ge adatoms on surfactant terminated Si(111) and Ge(111) surfaces. We address Si and Ge adsorption and migration on surfactant (Bi, Sb) terminated (111) surfaces of Si and strained Ge by comprehensively mapping potential energy surfaces using density functional calculations. The main migration paths are identified and corresponding energy barriers are reported. It is shown that the energy barrier for adatom migration through Bi or Sb surfactant trimers (by actually breaking the trimers) is virtually degenerate to the mechanism involving traveling of the adatom around the same surfactant structures. We also find a low-energy anchoring site that is suggested to act as a nucleation structure and to trigger the clustering process. These results suggest a fundamentally new picture for the whole Si(111) Bi(Sb) epitaxial process. [ABSTRACT FROM AUTHOR]

ABSTRACT We describe here the first example of the synthesis of 4-arm star poly(acrylic acid) for use as a water-soluble drag reducing agent, by applying Cu(0)-mediated polymerization technique. High molecular weight 4-arm star poly( tert-butyl acrylate) ( Mn = 3.0-9.0 × 105 g mol−1) was first synthesized using 4,4′-oxybis(3,3-bis(2-bromopropionate)butane as an initiator and a simple Cu(0)/TREN catalyst system. Then, 4-arm star poly( tert-butyl acrylate) were subjected to hydrolysis using trifluoroacetic acid resulting in water-soluble 4-arm star poly(acrylic acid). Drag reduction test rig analysis showed 4-arm star poly(acrylic acid) to be effective as a drag reducing agent with drag reduction of 24.3%. Moreover, 4-arm star poly(acrylic acid) exhibited superior mechanical stability when compared with a linear poly(acrylic acid) and commercially available drag reducing polymers; Praestol and poly(ethylene oxide). The linear poly(acrylic acid), Praestol, and poly(ethylene oxide) all showed a large decrease in drag reduction of 8-12% when cycled 30 times through the drag reduction test rig while, in contrast, 4-arm star poly(acrylic acid) demonstrated much higher mechanical stability. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 335-344 [ABSTRACT FROM AUTHOR]

ABSTRACT Well-defined star-shaped hydrophobic poly(ε-caprolactone) (PCL) and hydrophilic poly(ethylene glycol) (PEG) amphiphilic conetworks (APCNs) have been synthesized via the combination of ring opening polymerization (ROP) and click chemistry. Alkyne-terminated six arm star-shaped PCL (6-s-PCL x-CCH) and azido-terminated PEG (N3-PEG-N3) are characterized by 1H NMR and FT-IR. The swelling degree of the APCNs is determined both in water and organic solvent. This unique property of the conetworks is dependent on the nanophase separation of hydrophilic and hydrophobic phases. The morphology and thermal behaviors of the APCNs are investigated by SEM and DSC respectively. The biocompatibility is determined by water soluble tetrazolium salt reagents (WST-1) assay, which shows the new polymer networks had good biocompatibility. Through in vitro release of paclitaxel (PTX) and doxorubicin (DOX), the APCNs is confirmed to be promising drug depot materials for sustained hydrophobic and hydrophilic drugs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 407-417 [ABSTRACT FROM AUTHOR]

ABSTRACT A simple and convenient method for the synthesis of end functionalized polylactides (PLAs) under mild conditions by ring opening polymerization (ROP) in the absence of potentially toxic catalysts is described. Various alcohols were used as initiators in combination with Ca[N(SiMe3)2]2(THF)2 as the precatalyst in THF at room temperature. Tailored end functionalities were obtained in a controlled fashion. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS) and electrospray ionization quadrupole time of flight mass spectrometry (ESI-Q-ToF-MS) analysis were performed to investigate the end groups. The results confirmed that the end group fidelity was maintained in the isolated PLAs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 437-448 [ABSTRACT FROM AUTHOR]

ABSTRACT Ester-free silane and siloxane-based thiol monomers were successfully synthesized and evaluated for application in thiol-ene resins. Polymerization reaction rates, conversion, network properties as well as degradation experiments of those thiol monomers in combination with triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TATT) as ene component were performed and compared with formulations containing the commercially available mercaptopropionic ester-based thiol pentaerythritol tetra-3-mercaptopropionate. Kinetic analysis revealed appropriate reaction rates and conversions reaching 90% and higher. Importantly, storage stability tests of those formulations clearly indicate the superiority of the synthesized mercaptans compared with pentaerythritol tetra-3-mercaptopropionate/TATT resins. Moreover, photocured samples containing silane-based mercaptans provide higher glass transition temperatures and withstand water storage without a significant loss in their network properties. This behavior together with the observed excellent degradation resistance of photocured silane-based thiol/TATT formulations make these multifunctional mercaptans interesting candidates for high-performance applications, such as dental restoratives and automotive resins. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 418-424 [ABSTRACT FROM AUTHOR]

ABSTRACT In an effort to design efficient low-cost polymers for use in organic photovoltaic cells the easily prepared donor-acceptor-donor triad of a either cis-benzobisoxazole, trans-benzobisoxazole or trans-benzobisthiazole flanked by two thiophene rings was combined with the electron-rich 4,8-bis(5-(2-ethylhexyl)-thien-2-yl)-benzo[1,2- b:4,5- b′]dithiophene. The electrochemical, optical, morphological, charge transport, and photovoltaic properties of the resulting terpolymers were investigated. Although the polymers differed in the arrangement and/or nature of the chalcogens, they all had similar highest occupied molecular orbital energy levels (−5.2 to −5.3 eV) and optical band gaps (2.1-2.2 eV). However, the lowest unoccupied molecular orbital energy levels ranged from −3.1 to −3.5 eV. When the polymers were used as electron donors in bulk heterojunction photovoltaic devices with PC71BM ([6,6]-phenyl C71-butyric acid methyl ester) as the acceptor, the trans-benzobisoxazole polymer had the best performance with a power conversion efficiency of 2.8%. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 316-324 [ABSTRACT FROM AUTHOR]

ABSTRACT The synthesis and self-assembling of a thermoresponsive conjugate of hyaluronic acid (HA) and poly( N-vinylcaprolactam) (PVCL) is reported. Both polymers were end functionalized: HA via reductive amination, thereby introducing an azide endgroup to the chain end, and PVCL via thioetherification to introduce a propargyl group. The two were coupled with a copper assisted 'click' reaction into a bioconjugate composed of HA blocks with the molar mass 3,600 g mol−1 (1618 saccharide units) and PVCL blocks of 3,500 g mol−1 (∼25 repeating units). The cloud point temperature measured by transmittance was 50-51 °C in water. The calorimetrically observed phase transition temperature of PVCL in the conjugate increased by 2 °C to 47.7 °C, whereas the enthalpy of the phase transition was unaffected by the conjugation. HA-PVCL conjugate self-assembles in water upon heating into monodisperse, colloidally stable, hollow spherical particles whose size may be tuned with the heating rate of the solution. Slow and fast heating resulted in vesicles with the hydrodynamic radii of 443 or 275 nm, respectively. The heating rate did not, however, affect the cloud point. Salt did not noticeably affect the size of the polymer particles, presumably because of interactions between the HA and PVCL blocks. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 425-436 [ABSTRACT FROM AUTHOR]

ABSTRACT Two novel heterocycle-fluorene-heterocycle monomers, 2,2′-(9,9-dioctyl-9H-fluorene-2,7-diyl)dithiophene (Th-F-Th) and 5,5′-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(2,3-dihydrothieno[3,4-b][1,4]dioxine) (EDOT-F-EDOT), were synthesized via Stille coupling reaction and electropolymerized to form corresponding polymers P(Th-F-Th) and P(EDOT-F-EDOT). Furthermore, the optoelectronic properties of the obtained monomers and polymers were explored using cyclic voltammetry (CV), UV-vis, and emission spectra and in situ spectroelectrochemical techniques. The band gap values of monomers calculated by DFT were 3.75 eV for EDOT-F-EDOT and 4.03 eV for Th-F-Th, while that of P(EDOT-F-EDOT) and P(Th-F-Th) were brought down to 1.70 and 2.10 eV, respectively. Both polymers exhibited excellent redox activity and electrochromic performance. P(EDOT-F-EDOT) exhibited a maximum optical contrast of 25.8% at 500 nm in visible region with a response time of 1.2 s. In addition, the coloration efficiency of P(EDOT-F-EDOT) was calculated to be 220 cm2 C−1. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 325-334 [ABSTRACT FROM AUTHOR]

The most abundant naturally occurring terpene, α-pinene, which cannot be directly polymerized into high polymers by any polymerization method, was quantitatively converted under visible-light irradiation into pinocarvone, which possesses a reactive exo methylene group. The bicyclic vinyl ketone was quantitatively polymerized in fluoroalcohols by selective (99 %) ring-opening radical polymerization of the four-membered ring, which results in unique polymers containing chiral six-membered rings with conjugated ketone units in the main chain. These polymers display good thermal properties, optical activities, and contain reactive conjugated ketone units. Reversible addition fragmentation chain transfer (RAFT) polymerization was successfully accomplished by using appropriate trithiocarbonate RAFT agents, enabling the synthesis of thermoplastic elastomers based on controlled macromolecular architectures. [ABSTRACT FROM AUTHOR]

A mathematical model for describing the bulk free-radical polymerization of methyl-methacrylate was developed. This model includes a novel methodology for describing the diffusive step of the kinetic rate coefficients, which is based on geometric considerations and application of the Einstein diffusion Equation. The effect of polymer content and temperature on the Rp behavior is discussed in terms of the evolution of the interdependent parameters defining the Rp. The applicability of Smoluchowski equation and the importance of the translational diffusion of short radicals in the rate of termination reaction are questioned in this context. Similitudes and differences between the model results and experimental data are discussed including minima in the Rp curves at low conversions. [ABSTRACT FROM AUTHOR]

With the goal of improving processability of imide oligomers and achieving high toughness of thermosetting polyimides, a series of 4-phenylethynylphthalic anhydride (PEPA)-terminated imide oligomers prepared by the reaction of 2,3,3′,4′-diphenyl ether tetracarboxylic acid dianhydride (a-ODPA) and 3,4′-oxydianiline (3,4′-ODA) with different molecular weights (degree of polymerization: n = 1-9) were formed. The resultant oligomers with different molecular weights were characterized for their chemical architecture, cure behavior, thermal properties, solubility in organic solvents and rheological characteristics. Besides, the thermal properties and tensile test of cured polyimide films were also evaluated. The imide oligomer (degree of polymerization: n = 1) has some somewhat crystalline phase, and imide oligomers (degree of polymerization: n = 2-9) showed excellent solubility (40 wt%) in N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc) at room temperature. Furthermore, the rheological properties of imide oligomers showed very low melt viscosity and wider processing window. The cured films exhibited good thermal properties with the glass transition temperatures of 282-373 °C and 5 wt% thermal decomposition temperatures higher than 551 °C in nitrogen atmosphere. The elongation at break of the prepared films was found to be high (almost > 9.3%). [ABSTRACT FROM AUTHOR]

A systematical calculation is performed to explore the equilibrium phase behaviors of linear-dendritic triblock copolymer A B ( 2 g + 1 − 2 ) C 2 g + 1 ( g is the generation number of the block B, and G g is short for A B ( 2 g + 1 − 2 ) C 2 g + 1 ) from G1 to G5 by using self-consistent field theory. Eight phases are found: two-colored lamellar phase, three-colored lamellar phase, hexagonal phase, core shell hexagonal phase, tetragonal phase, core shell tetragonal phase, two interpenetrating tetragonal phase, lamellar phase with beads except disordered phase, by varying the interaction parameters between different blocks, the volume fractions of the blocks and the generation number. While investigating the effect of linear coil length on morphology, we find the longer linear length ( f A = 0.5) for G1, G2 can be beneficial to form the lamellar phase, however, tend to form hexagonal phase easily with generation number increasing from 3 to 5, and short linear length ( f A = 0.2) can be better for inducing hexagonal phase from G1 to G5. It becomes more and more difficult to phase separate with generation number increasing from 1 to 5 due to the architectural complexity. However, increasing the interaction parameters is helpful to facilitate phase separation. It is likely to offer new opportunity for designing nanomaterials and applying to template technology by finely controlling the dendron generations, length of the linear chain, interaction parameters of linear-dendritic triblock copolymers. [ABSTRACT FROM AUTHOR]

Wereport the design, synthesis, and physical/mechanical propertiesof graft copolymers containing semicrystalline polypropylene sidechains and amorphous ethylene/α-olefin copolymer backbones.These materials, a new class of semicrystalline, polyolefin-basedthermoplastic elastomers, are made in two steps. First, allyl-terminatedsyndiotactic or isotactic polypropylene macromonomers are synthesizedwith controlled microstructure and molecular weight using bis(phenoxyimine)titaniumor chiral ansa-zirconocene catalysts, respectively.Second, a pyridyl-amido hafnium catalyst is used to copolymerize themacromonomer, ethylene, and an α-olefin with precise controlof composition and side chain incorporation. With highly crystallinepolypropylene side chains and amorphous backbones of low glass-transitiontemperatures (<−55 °C), the samples have strain-to-breakvalues up to 1400% and elastic recovery above 85% at maximum strainsup to 1000%. The synthetic method described herein does not requirethe use of a living polymerization catalyst; in addition, the mechanicalproperties of these graft copolymers exceed those of the best linearblock polyolefins. [ABSTRACT FROM AUTHOR]

The single pulse–pulsed laserpolymerization–electronparamagnetic resonance (SP–PLP–EPR) method affords thedetailed kinetic analysis of acrylamide polymerization in aqueoussolution. Highly time-resolved SP–PLP–EPR experimentsfor 10 and 20 wt % AAm were first carried out at −5 °C,where only secondary propagating radicals (SPRs) occur. In a secondstep, the time evolution of midchain radicals (MCRs), produced fromSPRs by backbiting, was measured at higher temperatures. The terminationkinetics, including chain-length dependent termination of SPRs, thebackbiting rate of SPRs, and the propagation rate of MCRs were determined.The rate coefficients from SP–PLP–EPR in conjunctionwith the known propagation rate coefficient of SPRs, enable the simulationof the kinetics and product properties of AAm radical polymerizationsin aqueous solution. [ABSTRACT FROM AUTHOR]

Length of the terminal alkyl chains at dicyanovinyl (DCV) groups of two dithienosilole (DTS) containing small molecules ( DTS(Oct)2-(2T-DCV-Me)2 and DTS(Oct)2-(2T-DCV-Hex)2 ) is investigated to evaluate how this affects the molecular solubility and blend morphology as well as their performance in bulk heterojunction organic solar cells (OSCs). While the DTS(Oct)2-(2T-DCV-Me)2 (a solubility of 5 mg mL−1) system exhibits both high short circuit current density ( Jsc) and high fill factor, the DTS(Oct)2-(2T-DCV-Hex)2 (a solubility of 24 mg mL−1) system in contrast suffers from a poor blend morphology as examined by atomic force morphology and grazing incidence X-ray scattering measurements, which limit the photovoltaic properties. The charge generation, transport, and recombination dynamics associated with the limited device performance are investigated for both systems. Nongeminate recombination losses in DTS(Oct)2-(2T-DCV-Hex)2 system are demonstrated to be significant by combining space charge limited current analysis and light intensity dependence of current-voltage characteristics in combination with photogenerated charge carrier extraction by linearly increasing voltage and transient photovoltage measurements. DTS(Oct)2-(2T-DCV-Me)2 in contrast performs nearly ideal with no evidence of nongeminate recombination, space charge effects, or mobility limitation. These results demonstrate the importance of alkyl chain engineering for solution-processed OSCs based on small molecules as an essential design tool to overcome transport limitations. [ABSTRACT FROM AUTHOR]

Radical polymerization of unpolymerizable sterically hindered butadiene was successfully performed in the nanochannels of porous coordination polymers because of the effective suppression of unfavourable termination reactions. Microstructures of the resulting polymer could also be tuned depending on the structure of the porous hosts. [ABSTRACT FROM AUTHOR]

This article will review our current understanding of transcription elongation and termination in E. coli. We discuss why transcription elongation complexes pause at certain template sites and how auxiliary host and phage transcription factors affect elongation and termination. The connection between translation and transcription elongation is described. Finally we present an overview indicating where progress has been made and where it has not. [ABSTRACT FROM AUTHOR]

Superhydrophobic fluorinated polystyrene microspheres were prepared by distillation precipitation polymerization of 4-fluorostyrene (FSt), styrene (St), with divinylbenzene (DVB) as cross-linker in acetonitrile in the absence of any stabilizer. Both the fluorine contents and sizes of the polymeric microspheres were tuned via altering the feed ratio of the fluorinated monomers for polymerization. The films via casting the suspension with fluorinated microspheres exhibited a superhydrophobic behavior with contact angles larger than 150°. The resultant microspheres were characterized by transmission electron microscopy (TEM), Fourier-transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), ion chromatography, and contact angle system. [ABSTRACT FROM AUTHOR]

Poly high internal phase emulsion (PolyHIPE) monolith has attracted many attentions for easy preparation, precise control on its porous structure, and excellent properties. In many applications, however, post-modification is needed to introduce functional groups onto their surfaces in order to achieve specific separation ability, reactivity or absorptivity, etc. In the current work, we proposed one-pot interfacial polymerization method to achieve composite PolyHIPEs with functional surface in one pot. It was realized by three strategies in preparing typical polystyrene PolyHIPEs from water-in-oil (W/O) HIPE: (1) introducing water-soluble initiator of potassium persulfate (KPS) and monomer of acryl acid (AA) into aqueous phase under conventional HIPE polymerization, (2) introducing KPS and AA into aqueous phase under high internal phase emulsions via reversible addition-fragmentation chain transfer (HIPE RAFT) living radical polymerization, and (3) employing reactive amphipathic MacroRAFT agent as surfactant. All these three strategies proved to be effective to generate a composite structure with different surface and bulk compositions. AA enrichment on the surface was verified by X-ray photoelectric energy spectrum (XPS) etching. Their effects on the morphology and mechanical properties were also studied. [ABSTRACT FROM AUTHOR]

The effect of hydrogen adsorption on the electronic structures and optical properties of undoped and Mg-doped ZnO 000 1 ¯ polar surface was investigated using the first principles method. The obtained results show that hydrogen adsorption is more favored on Mg doped-ZnO 000 1 ¯ surface than onto the clean surface, and this makes Mg-doped ZnO and Mg x Zn 1 − x O more efficient for H storage or gas sensing applications than undoped ZnO. On the other hand, our results show that the hydrogen adsorption on the Mg doped surface is energetically very preferable when the surface was prepared under O-rich conditions. We have also examined the effect of H adsorption on the optical properties of the surface. [ABSTRACT FROM AUTHOR]

Density Functional Theory and X-ray standing wave atomic imaging are combined to develop models of platinum overlayers, patches and small particles on (001) surfaces of SrTiO 3 . The higher coverage (0.3 ML nominal Pt) experimental result matches best to a simple 1 × 1 surface model. For lower coverage (0.1 ML) a Ti deficient TiO 2 double layer termination is identified as most favorable. A simple model is developed by which XSW amplitudes can be used to infer the aspect ratio of surface structures. [ABSTRACT FROM AUTHOR]

Precisionfunctionality is the key feature of next-generation radical polymerizationenabling the implementation of applications such as controlled drugdelivery, self-healing material design, and optoelectronic materials.The incorporation of functionality is however diametrically opposedto diffusion-controlled growth-inhibiting termination reactions. Thefundamental bottleneck remains the identification of a generic andflexible protocol to accurately map the short–longtermination reactivity. Herein, we introduce a unique frameworkbased on the reversible addition–fragmentation chain transfer–chainlength dependent–termination (RAFT-CLD-T) method that encompassesan extension of state-of-the-art fundamental theories and a correctionfor possible polymer matrix effects. Applied to methyl methacrylate(MMA) polymerization, the short–longterminationreactivity is accurately quantified for the first time. Data analysisreveals the deficiency of currently used simplified models to describethe true short–longtermination reactivityand the dominance of short-chain diffusivity. The proposed frameworkand insights are a turnkey prerequisite for the fundamental understandingof radical polymerization processes and to complete current macromoleculardiffusion theories. [ABSTRACT FROM AUTHOR]

We study the electronic structures and the magnetoelectric (ME) effect in Fe/KNbO 3 superlattices theoretically. The interior KNbO 3 layers in superlattices with the NbO 2 terminations are insulating. While they are metallic for the KO terminations. The interface Fe Nb and Fe O bonds induce large magnetic moments on Nb and O atoms. The magnitude of the induced magnetic moments is related to the polarization direction of the KNbO 3 layers. We obtain a large ME effect in NbO 2 -terminated superlattices. However the ME effect is negligible in KO-terminated superlattices due to the opposite sign of variations of magnetic moments on O and Fe at two interfaces. [ABSTRACT FROM AUTHOR]

In this work, Macro-Reversible addition fragmentation termination (RAFT) agents based on poly(ethylene glycol) (PEG) possessing different molecular weights and bearing benzoyl xanthate moieties were synthesized by the reaction of PEG potassium xanthate salts with benzoyl chloride, 4-methyl benzoyl chloride and 4-chloro benzoyl chloride. Controlled free radical polymerization of the styrene were carried out in the presence of these macro-RAFT agents using 2,2′-azobisizsobutyronitrile (AIBN) as an initiator to yield PS-b-PEG-b-PS block copolymers. The linear kinetic plot ln [M]o/[M] vs. polymerization time indicated that was first order with reference to monomer concentration. The block copolymerization possessed controlled/living character. The controlled character of the RAFT polymerization of the styrene was confirmed by the formation of narrow polydispersity of the polymers, linear increases in the molecular weight with polymerization time and molecular weight of the products that agreed well with theoretical values. Polymers having relatively narrow molecular weight distributions and predetermined number average molecular weights were obtained by the RAFT polymerization of the styrene. However, molecular weights of the polymers deviated from the theoretical values when low molecular weight RAFT agents are used. The results indicate that PEG benzoyl xanthate RAFT agents can more efficiently control the polymerization comparing methyl or chlorobenzoyl derivatives. The block copolymers were characterized by spectroscopic and GPC methods. [ABSTRACT FROM AUTHOR]

A mathematical model of RAFT polymerization processes is presented capable of predicting the full molecular weight distribution (MWD) through the use of probability generating functions (pgf). The bivariate distribution of the intermediate RAFT species is calculated. The model is able to work with the three kinetic mechanisms currently under discussion for explaining the observed behavior of this type of polymerization. For comparison purposes, the population balances are also solved by direct integration of the resulting equations. The results show that the pgf technique allows obtaining accurate solutions with very small computational times for systems of any average molecular weight. Spurious oscillations observed in the high molecular weight tail of the MWD can be easily disregarded. A sensitivity analysis over several of the kinetic constants is also performed, showing the effects of changing their values over several orders of magnitude. This analysis aims to showcase the enormous potential of the pgf technique for modeling and optimization of complex polymerization kinetics. [ABSTRACT FROM AUTHOR]

Recently, the requirement for fast, low-cost, and highly reliable methods has triggered the development of next-generation DNA sequencing technologies. In addition to overcoming the restrictions in Sanger sequencing methods, large-scale genetic data have provided the development of different analysis methods. In this paper, widely used next-generation sequencing platforms, the analyses of the data obtained, and the applications of these technologies are discussed. [ABSTRACT FROM AUTHOR]

ABSTRACT It is now well established that controlling the grafted chain lengths and densities on nanoparticle surfaces determines the effective interactions between particles, and their assembly. Here, we present unusual kinetic results for achieving grafted chain lengths longer than the free chains using reversible addition-fragmentation chain transfer (RAFT) polymerization and discuss the limitations to obtaining polymer grafting density higher than ∼0.06 chains/nm2. We observe that surface initiated polymerization grows faster than the free chains in solution with high RAFT agent coverage (1.95 agents/nm2) on nanoparticles. The time-dependence of graft density suggests that activation of the anchored chain transfer agent (CTA) is limited by the diffusion of macro-radicals within growing grafts. Thus, radical transfer and exchange reactions become inefficient between grafts and free polymer, and convert the surface-initiated RAFT mechanism to a free radical polymerization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1700-1705 [ABSTRACT FROM AUTHOR]

Abstract: Enyne cross metathesis of terminal 1,3-diynes with various alkenes afforded two products of distinctive connectivity, as the result of a uniform mode of initiation but different modes of termination events with or without metallotropic [1,3]-shift. Steric and electronic factors of the substituents on the 1,3-diynes play an important role in controlling the metallotropic [1,3]-shift of the propagating alkylidene intermediates and their regioselective trapping to the final products. [Copyright &y& Elsevier]

[Display omitted] • A family of three group IV diamine bis(phenolate) catalysts synthesized and fully characterized. • Zr based catalyst is the most active towards 1-decene oligomerization using ([Ph 3 C][B(C 6 F 5) 4 ]) as an activator at 80 °C. • Molecular weight of the obtained oligomers showed a close relationship with employed metal center. • Initiation and propagation first order toward 1-decene and catalyst concentration, independent from an excess of cocatalyst. • The increase of oligomerization temperature shifted PDI (Mw/Mn) to the higher values. A family of three group IV based diamine bis(phenolate) catalysts, [M{2,2ʹ-(OC 6 H 2 -4,6-tBu 2) 2 NHC 2 H 4 NH}(OiPr) 2 ] (M = Ti (Cat1), Zr (Cat2), and Hf (Cat3)) were synthesized and characterized. These complexes were employed in 1-decene oligomerization using ([Ph 3 C][B(C 6 F 5) 4 ]) as an activator at 80 °C. NMR spectra of the di(isopropoxy) complexes confirmed C 2 -symmetrical structures. Cat2 demonstrated the highest activity followed by Cat3 and Cat1 , whereas tacticity Cat1 > Cat2 > Cat3. The origin of this different performance was unveiled by DFT calculations. Interestingly, the increase of oligomerization temperature shifted PDI to the higher values. Moreover, kinetic studies employing population balance approach have been conducted, being outstanding that initiation rate constants were lower than propagation ones by a factor of 100. The precise study of termination reactions by NMR revealed that the significant termination reaction was the creation of two types of unsaturated bonds, i.e. vinylidene and vinylene. The obtained oligomers had viscosity index and pour point values comparable with commercial oils. [ABSTRACT FROM AUTHOR]

A correction to the article "Termination Mechanism of the Radical Polymerization of Acrylates" that was published in the previous issue is presented.