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Metal organic frameworks (MOFs) have been suggested as promising materials for application in the degradation of chemical warfare agents, with the majority of studies to date focusing on nerve agents. One of the most prominent MOFs used in the detoxification of nerve agents is UiO-66, which is of interest as a future nerve agent decontaminant. However, blister agents, which constitute one of the most toxic and highly reactive categories of chemical agents, are yet to be examined as gas-phase decontamination targets using MOF structures. In this study, a novel type of UiO-66 with a smaller particle size, namely, UiO-66S, was used as a decontaminant for the blister agent simulant, 2-chloroethyl ethyl sulfide (2-CEES). The gas-phase chemical adsorption and decomposition of 2-CEES were demonstrated for the first time, with an estimated t1/2 of 1.34 h. This value is the highest reported value for an MOF in gas-phase reaction conditions. The obtained nontoxic degradation products were identified, and the reaction mechanism was studied using density functional theory calculations. Furthermore, the synthesized UiO-66S catalyst also exhibits superior catalytic ability toward nerve agent simulants (diisopropyl fluorophosphate).The results of the study provide a firm basis for the use of UiO-66S as a future decontaminant for both nerve and blister agents.

An acid-base bifunctional zeolitic imidazolate framework catalyst (ZIF8-A61-SO3H) with amine and sulfonic acid groups was successfully prepared through simple two step post-synthetic modification: preparation of amine-functionalized ZIF-8 with amine contents of 61% (ZIF8-A61) by the ligand exchange of 2-mIM with 3-amino-1,2,4-triazole (Atz), followed by the sulfonic acid functionalization by the ring-opening reaction of 1,3-propanesultone with –NH2 groups in ZIF8-A61. Amine-functionalized ZIF8-A materials with difference amine contents (15%, 34%, and 61%, respectively) were also prepared by controlling the synthesis time. All obtained ZIF catalysts evaluated as a heterogeneous catalyst for one-pot deacetalization-Knoevenagel condensation tandem reaction. Compared with ZIF-8 and amine-functionalized ZIF-8 catalysts, ZIF8-A61-SO3H catalyst showed good catalytic performance with 100% conversion of the reactant and 98% selectivity of the final Knoevenagel product. An enhanced catalytic activity can be attributed to the co-existence of site-isolated acid-base groups on the ZIF8-A61-SO3H catalyst in close proximity. The heterogeneous nature of the catalytic system was confirmed by a hot-filtering test and the catalyst also exhibited reusable in the five repeated cycles. A plausible catalytic mechanism of deacetalization-Knoevenagel condensation reaction over ZIF8-A61-SO3H was also proposed.

Development of new hole-transport layer (HTL) materials for organic photovoltaic (OPV) applications is one crucial issue to mitigate such limitations of low power efficiency, processibility, and stability derived from poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a common HTL material. To this end, poly(3-hexylthiophene) (P3HT)-based diblock copolymers including the different ratios between polystyrene (PSty) or/and poly(neopentyl styrene sulfonate) (PNSS) as a second block segment were designed and then used for incorporating with single wall carbon nanotubes (SWCNTs) to form potentially self-dopable nanocomposites. The structure of fabricated P3HT-based diblock copolymer/SWCNT nanocomposites was examined by microscopic and spectroscopic characterizations, exhibiting a charge transfer behavior between P3HT and SWCNT, and growth of the P3HT crystalline phase along the SWCNT surface with a form of the conducting path. The acquired SWCNT nanocomposites exhibited good solubility and dispersion in various organic solvents including toluene, chlorobenzene, THF, chloroform, and DMF, which are good solvents for the PSty or/and PNSS neutral second block. The concept for the neutralized second block by protecting groups can prevent the poisoning ITO substrate by water contamination as shown in the conventional aqueous PEDOT-PSS solution. Notably, the PNSS constituent in the nanocomposite was merely acidified to give in-situ sulfonic acid groups in PSty by simple thermolysis process at 160 °C for 30 min after a solution process for fabrication of a thin film. The thermolysis step provided efficient doping of P3HT by PSS, in which the thiophene groups worked as Bronsted base are protonated by taking protons from sulfonic acid groups and then lead to a form of ionic bonds between cationic thiophene and anionic sulfonate groups. In addition, the formed ionic bonds in the nanocomposites led to an insoluble thin film, which has a good advantage for the further solvent process without substantial damages. The beneficial features of the conducting path along SWCNT and the efficient doping of P3HT by PSS in the acquired nanocomposites led to ca. 5-fold higher electrical conductivity (3.16 S cm−1) and similar work function (5.1 eV) in comparison to water contained commercial PEDOT:PSS (0.6 S cm−1 and 5.0 eV, respectively). As such, the rationally designed potentially self-dopable SWCNT nanocomposites can be one of the promising alternatives beyond the commercial PEDOT: PSS HTL material.

Various failure modes derived from the electrochemical migration (ECM) through the dielectric polymer layers have been considered critical issues in the electronic devices. Herein, we for the first time suggested the rationally designed epoxy/zeolitic imidazolate framework-8 (ZIF-8) nanocomposite materials for efficient suppression of copper ion migration based on the plausible reaction mechanisms of metal metathesis addressed by sequential cleaving and ligating between metal ions (Zn2+ and Cu2+) and 2-methylimidazole (2-mim) ligands. The fabrication process for epoxy/ZIF-8 (EZ) nanocomposites was first examined to optimize the crosslinking system. The capability of the metal ion capture in the EZ nanocomposites was examined using the aqueous solution containing Cu2+ ions. In addition, the ECM suppression properties were evaluated using the thermal humidity bias (THB) model testing. The representative model investigations with the EZ nanocomposites exhibited substantially enhanced copper ion adsorption and suppression of copper migration in comparison to those of epoxy. Hence, the EZ nanocomposites can be one promising material to alleviate the undesired ECM behavior in electronic device applications.

Two series of water-soluble metalloporphyrin-cored amphiphilic star block copolymers were synthesized by controlled radical polymerizations such as atom transfer radical polymerization (ATRP) and reversible addition fragmentation chain transfer (RAFT), which gave eight amphiphilic block copolymer arm chains consisting of poly(n-butyl acrylate-b-poly(ethylene glycol) methyl ether methacylate) (PnBA-b-PEGMEMA, Mn,GPC = 78,000, Mw/Mn = 1.2, 70 wt% of PPEGMEMA) and poly(styrene-b-2-dimethylamino ethyl acrylate) (PS-b-PDMAEA, Mn,GPC = 83,000, Mw/Mn = 1.2, 67 wt% of PDMAEA), yielding porphyrin(Pd)-(PnBA-b-PPEGMEMA)8 and porphyrin(Pd)-(PS-b-PDMAEA)8, respectively. Obtained metalloporphyrin polymer photocatalysts were homogeneously solubilized in water to apply to the removal of chlorophenols in water, and was distinguished from conventional water-insoluble small molecular metalloporphyrin photocatalysts. Notably, we found that the water-soluble star block copolymers with hydrophobic–hydrophilic core–shell structures more effectively decomposed the chlorophenol, 2,4,6-trichlorophenol (2,4,6-TCP), in water under visible light irradiation (k = 1.39 h−1, t1/2 = 0.5 h) in comparison to the corresponding water-soluble star homopolymer, because the hydrophobic core near the metalloporphyrin effectively captured and decomposed the hydrophobic chlorophenols in water.

The carbon fiber reinforced plastics (CFRP) are still limited the used in the automotive industry mainly by the weak interfacial adhesion between the fiber and polymer matrix. Herein, to improve interfacial interactions between the carbon fiber (CF) and polypropylene (PP) matrix, poly(dimethylaminoethyl methacrylate)-b-poly(methyl methacrylate) (PDMAEMA-b-PMMA, PDM) compatibilizers are applied to functionalize the CF surface through a covalent bonding with epoxide groups on the chemically modified CF surface with tertiary amines in the PDMAEMA block, which induced intermolecular entanglement with PP chains with the PMD compatibilizers. The acquired compatibilizer-functionalized CF (CECF) was applied to fabricate PP composites by a melt-mixing method. The highly improved interfacial adhesion between the CECF and PP was confirmed by evaluating thermal, morphological, rheological, and mechanical properties. Based on the significantly enhanced interfacial adhesion, notably, the tensile strength and modulus of the CECF/PP composite exhibited a massive increase by ca. 312% and 664%, respectively, relative to those of the PP resin. The Ashby plot facilitated understanding that the acquired mechanical properties of the CECF/PP composite showed a relatively ideal position compared to reported PP composites and centered on the commercially available region in automotive components.

Pourable and room temperature flowable ladder-structured polysilsesquioxanes were synthesized and applied as functional optical hard coatings. Organic functional group type (propyl, hexyl, octyl, dodecyl) and their copolymer composition with UV-curable methylacryloxypropyl group were selected as to control both pre-cured viscosity and final mechanical properties independent of molecular weight. Ladder-structured polysilsesquioxanes with longer alkyl side chains exhibited higher fluidity and flexibility while maintaining its optical property and mechanical strength. The solvent-free processability of our synthesized materials along with their superior optical and mechanical properties over commercial solvent-based hard coatings suggest the high value of our hybrid materials for the coatings industry.

To data, combination of Pt-based bimetallic nanocrysatals and the graphene support have significantly contributed to enhance the oxygen reduction reaction (ORR) performance relative to electrocatalysts based on monometallic Pt nanoparticles (NPs) primarily due to the unique ligand effects and benefits of the carbon support. In this study, we propose a new structure of bimetallic electrocatalysts to realize the synergistic effects on the ORR performance through effective integration of the fine-sized Pt NPs, PdPt bimetallic nanocrystals, and non-covalently functionalized graphene with ionic polymers. The facile wet-chemical methods were applied to synthesize fine-sized (2–5 nm) spherical Pt NPs doped large-sized (20–50 nm) non-spherical PdPt bimetallic NPs on the electronically negative ionic polymer-functionalized graphene support (Pt-on-PdPt/fG). This Pt-on-PdPt/fG with synergistic effects based on enlarged active surface area, ligand, and interfacial linking effects, exhibits substantially enhanced ORR activity (specific activity: 1.89 mA c m Pt − 2 at 0.9 VRHE) and durability in comparison to the commercial Pt/C (specific activity: 0.23 mA c m Pt − 2 at 0.9 VRHE). To this end, the effective integration of newly designed fine-sized Pt NPs doped bimetallic nanocrystals and unique graphene supports with the well-interactive ability could be a good platform to develop the advanced electrocatalysts for the efficient ORR.

Heteroleptic ruthenium-complexed ladder-like structured polysilsesquioxane (LPSQ-Ru) was synthesized by post coordination reaction of bidentate ligand side chains in LPSQ with reactive Ru(II) complexes, which was well characterized by 1H and 29Si NMR, FT-IR, and spectroscopic techniques. The photophysical properties of LPSQ-Ru were examined by UV and PL analyses in both solution and solid states, comparing to analogous polymers of ruthenium-complexed polystyrene (PS-Ru). Obtained absorptions of LPSQ-Ru and PS-Ru were broadened ranging from 390-490 nm regardless of the states. However, LPSQ-Ru exhibited higher and shaper PL emission spectrum in comparison to that of PS-Ru, particularly in the solid state, because Ru-complexes in LPSQ were much effectively isolated, preventing their aggregations due to the rigid double strained siloxane backbone. This extinguished photophysical property in LPSQ-Ru kept after intensive thermal treatment at 250 °C for 90 min, which was not achieved in PS-Ru (~5-fold decrease). These differences originated from the backbone structures were also appeared in electrochemical properties in the solid states.

Mixed matrix membranes (MMMs) are an attractive platform for challenging gas separations since they are the state-of-the-art scalable molecular sieve membranes. Here, the commercially attractive polysulfone (PSF) was grafted by poly(polyethylene glycol) methyl ether methacrylate (PEG) side chains to improve the interfacial interaction with zeolitic imidazolate framework-8 (ZIF-8) nanoparticles and the affinity towards C3H6 for enhanced C3H6/C3H8 separation performance. The PSFPEG graft copolymers monotonically increased the intersegmental distance of polymer chains with increasing the PEG contents based on the XRD results and the density functional theory calculations. Also, the cross-sectional SEM images of MMMs visualized that the interfacial adhesion between ZIF-8 and polymer was improved as the PEG content increased. Both DSC and FT-IR analyses revealed that such an enhanced interfacial adhesion was attributed to a combination of flexible nature of PEG side chains and various chemical interactions. More importantly, the PSFPEG73/ZIF-8 (65/35 vol/vol) MMM enhanced both C3H6 permeability and C3H6/C3H8 permselectivity compared to the PSF/ZIF-8 counterpart by 57% and 55%, respectively. Besides, the equimolar C3H6/C3H8 mixed gas permeation isotherm exhibited that the PSFPEG73/ZIF-8 (65/35 vol/vol) MMM enhanced the plasticization resistance against C3H6 compared to the PSF/ZIF-8 counterpart (e.g., C3H6-induced plasticization pressure of 5 vs. 3 atm), demonstrating the significance of the interfacial interaction.

Palladium nanoparticles on ionic polymer-doped graphene (Pd–IPG) nanocomposite catalysts have been investigated for efficient Suzuki coupling reactions. This combination effected highly accelerated Suzuki coupling reactions due to several advantageous features associated with the flanking ionic polymer part of the catalyst system. These include a high level of Pd incorporation, excellent dispersion stability, and increased accessibility and diffusion of the substrates onto the surface of Pd NPs. The enhanced availability of the Pd catalyst to the reacting substrates is believed to allow for ca. 16-fold higher catalytic activity than that of Pd–graphene without the ionic polymer. Moreover, high recycling capability of the catalyst (10 times) in combination with excellent product yields (>96%) and no significant leaching of the catalyst upon hot-filtration test suggest that the Pd–IPG nanocomposite catalysts have high reusability with significant retention (>95%) of the Pd species.

A region suffering from an attack of a nerve agent requires not only a highly sorptive material but also a fast-acting catalyst to decontaminate the lethal chemical present. The product should be capable of high sorptive capacity, selectivity and quick response time to neutralize the long lasting harmful effects of nerve agents. Herein, we have utilized organophosphorus hydrolase (OPH) as a non-toxic bio-catalytic material held in with the supporting matrix of poly-β-cyclodextrin (PCD) as a novel sorptive reinforced self-decontaminating material against organophosphate intoxication. OPH coated PCD (OPH-PCD) will not only be providing support for holding enzyme but also would be adsorbing methyl paraoxon (MPO) used as a simulant, in a host-guest inclusion complex formation. Sorption trend for PCD revealed preference towards the more hydrophobic MPO against para-nitrophenol (pNP). The results show sorption capacity of 1.26 mg/g of 100 μM MPO with PCD which was 1.7 times higher compared to pNP. The reaction rate with immobilized OPH-PCD was found to be 23% less compared to free enzyme. With the help of OPH-PCD, continuous hydrolysis (100%) of MPO into pNP was observed for a period of 24 h through packed bed reactor with good reproducibility and stability of enzyme. The long-term stability also confirmed its stable nature for the investigation period of 4 days where it maintained activity. Combined with its fast and reactive nature, the resulting self-decontaminating regenerating material provides a promising strategy for the neutralization of nerve agents and preserving the environment.

A series of well-defined hard–soft–hard triblock copolymers were synthesized by Ru-based atom transfer radical polymerization (ATRP) (MWD < 1.26) in order to examine their electromechanical properties under electric fields. The obtained methacrylate based triblock copolymers consisted of poly(dodecyl methacrylate) (PDMA) soft middle block segments and three different hard block segments with poly(methyl methacrylate) (PMMA), poly(tert-butyl methacrylate) (PtBMA), and their random copolymers (PMTDTMTs). Polar acidified triblock copolymers were also prepared by deprotecting tert-butyl groups in tBMA-incorporating hard block segments through simple thermal treatment at 200 °C for 120 min, which in situ gave poly(methacrylic acid) (PMAA) and its random copolymers (PAMDMA) in the hard block segments. SAXS and AFM studies indicated that these triblock copolymers showed well-organized phase separations with different domain sizes, which were strongly dependent on the amount of bulky PtBMA or polar PMAA in the hard block segments. In addition, these triblock copolymers had a variety of morphologies affecting their mechanical (elastic modulus) and electrical (dielectric constant) properties, leading to a tuning of their electromechanical properties. The transverse strains of these triblock random copolymers as a function of an applied electric field indicated that the PTMDMT series possessed the best electromechanical properties, exhibiting an 11-fold enhancement relative to the corresponding acidified polymer PAMDMA at 50 Vpp μm−1 due to a dramatic decrease of the elastic modulus from 4.04 to 0.05 MPa in spite of an increase of the dielectric constant from 3.6 to 5.1. In situ SAXS analysis under an electric field showed that these bulk strains originated from nano-structured microdomain changes.

A series of thiol-ene UV-curable inorganic–organic hybrid polysilsesquioxanes of various phenyl:methacryloxypropyl and phenyl:mercaptopropyl copolymer compositions were synthesized in one-batch using a base-catalyzed system. These thermoplastic photocurable ladder-like structured materials were examined as scratch-resistant, hard-coating materials on both glass and PET substrates. The unique fully condensed structure of the hybrid polymers allowed for simplified processing and through variation of the organic functional group, films with high transparency, tunable refractive indices in the range of 1.467–1.546, pencil hardness values of 9H, and high nanoindentation modulus were obtained (7 GPa). These scratch-resistant polysilsesquioxanes may provide insight into the different organic functional group compositions which allow for optimal mechanical properties.

A ladder-like structured poly(mercaptopropyl)silsesquioxane (LPMPSQ) was synthesized in one-bath, under mildly basic conditions at room temperature. Obtained LPMPSQ was utilized as a macroinitiator for thiol-ene graft photopolymerization of various vinyl monomers to give hard, soft, hydrophobic, and hydrophilic graft copolymers with low PDI (

Carbon nanotubes (CNTs) coated by compatibilizer (P3HT-PMMA) imparted sta-ble dispersion in organic solvents and polymer matrix (P(VDF-TrFE)). The compatibility be-tween CNTs with P3HT-PMMA was con rmed by measuring Raman spectroscopy. CoatedCNTs were then blended with P(VDF-TrFE) (70:30 mol%) to obtain polymer nanocompositesby solution- casting process. Polymer nanocomposites showed enhanced electrical characteris-tics, as nanocomposites near the threshold of the transition between P(VDF-TrFE) insulatorand CNT conductor revealed great improvement of electrical conductivity up to 10-6 S/cmat 1 KHz. Electromechanical properties of the polymer nanocomposite were examined as afunction of electric eld.

A series of epoxy-functionalized inorganic–organic hybrid ladder-like structured polysilsesquioxanes were synthesized in one-batch via a base-catalyzed co-solvent system. Two types of epoxy functionalities were examined: aliphatic and cycloaliphatic. Obtained polymeric epoxy-functionalized ladder-like polysilsesquioxanes were cationically photopolymerized under UV irradiation over glass and plastic substrates. Obtained cross-linked films were examined as hardcoating materials as their thermal, optical, mechanical, and barrier properties were studied. These materials showed superior thermal properties (Td > 400 °C), high optical transparency (>95%), high pencil hardness (4H–9H), low dielectric constant (3.0–3.6), and good barrier properties (WVTR < 101 g m−2 day−1, OTR < 102 g m−2 day−1).

The first demonstration of polymer nanowire (PNW) crystals based on a diketopyrrolopyrrole-based copolymer (i.e., PDTTDPP), and their application to field-effect transistors (FETs) is reported. Remarkably, transmission electron microscopy and selected area electron diffraction analyses of the PNW reveal its single-crystalline (SC) nature. FETs fabricated of a SC PNW exhibit a maximal charge carrier mobility of ≈7.00 cm(2) V(-1) s(-1) , which is almost one order of magnitude higher than that of the thin-film transistors made of the same polymer (PDTTDPP).

A composite membrane of silica (SiO2)/sulfonated poly (ether ether ketone) (SPEEK) nanofiber mat impregnated with Nafion was fabricated and evaluated for its potential use as a proton conductor for high temperature polymer electrolyte membrane fuel cells. The supporting SiO2/SPEEK composite nanofibrous skeleton was prepared via electrospinning of a mixture of SPEEK solution and silica sol prepared from tetraethyl orthosilicate (TEOS). The control of hydrolysis and condensation of TEOS enabled to form entangled SiO2 networks miscible to SPEEK solution. The prepared SiO2/SPEEK nanofiber mat was impregnated with Nafion® to completely fill the inter-fiber voids to prepare a dense membrane. The morphology of the nanofiber mat and the composite membrane were observed by scanning electron microscopy and the presence of SiO2 and SPEEK in the prepared nanofibers was confirmed by FTIR spectroscopy. Proton conductivity and swelling of the membrane were measured. The H2/O2 single cell test using the composite membrane as a PEM was performed. At a high temperature and low humidity condition (120 °C and 40 % RH), the maximum power density was 170 mW/cm2 for the Nafion-impregnated SiO2/SPEEK (40/60 w/w) composite nanofiber membrane that was 2.4 times higher than recast Nafion (71 mW/cm2) while SPEEK film failed.

A new photocurable ladder-like poly(phenyl-co-mercaptopropyl)silsesquioxane (LPPMPSQ) was synthesized in one pot via base catalyzed hydrolysis-polycondensation of a comonomer mixture of phenyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane. Obtained LPPMPSQ was characterized by 1H NMR, FT-IR, 29Si NMR, TGA, and the electrical (k = 3.6) and mechanical properties (surface modulus = 4.9 GPa) found to be suitable for application as a photocurable gate dielectric material.

The design of amphiphilic polymer compatibilizers for solubility manipulation of CNT composites was systematically generalized in this study. Structurally tailored multiamphiphilic compatibilizer were designed and synthesized by applying simple, high-yield reactions. This multiamphiphilic compatibilizer was applied for noncovalent functionalization of CNTs as well as provided CNTs with outstanding dispersion stability, manipulation of solubility, and hybridization with Ag nanoparticles (NPs). With regard to the dispersion properties, superior records in maximum concentration (2.88-3.10 mg/mL in chloroform), and mass ratio of the compatibilizer for good CNT dispersion (36 wt %) were achieved by MWCNTs functionalized with a multiamphiphilic block copolymer compatibilizer. In particular, the solubility limitations of MWCNT dispersion in solvents ranging from toluene (nonpolar) to aqueous solution (polar) are surprisingly resolved by introducing this multiamphiphilic polymer compatibilizer. Furthermore, this polymer compatibilizer allowed the synthesis of the hybrid CNT nanocomposites with Ag nanoparticles by an in situ nucleation process. As such, the multiamphiphilic compatibilizer candidate as a new concept for the noncovalent functionalization of CNTs can extend their use for a wide range of applications.

Diblock star polymers were synthesized via atom transfer radical polymerization from a palladium porphyrin macroinitiator. The arms of the star polymers had an amphiphilic design, with the central Pd-porphyrin surrounded by a relatively hydrophobic block of poly(butyl acrylate) and terminated by a hydrophilic block of poly(oligoethyleneglycol monomethylether monomethacrylate). The size of both the interior and exterior blocks of the polymer arms were tuned over a wide range of molecular weights with the exterior block used to solubilize the stars in polar media. The star polymers showed enhanced reactivity in the oxidation of 2-furaldehyde relative to a small molecule porphyrin, suggesting that the polymer backbone aids with catalytic turnover. Oxygen diffusion studies indicate that the polymer backbone shields the porphyrin excited state from oxygen quenching. Shielding is independent of molecular weight and polymer composition, but it is not pronounced enough to retard the rate of singlet oxygen generation under preparative photooxidation conditions.

Star poly(methyl methacrylate)s (P*) of various arm lengths and core sizes were synthesized in high yields by the polymer linking reaction in Ru(II)-catalyzed living radical polymerization. The yields of the star polymers were strongly dependent on the reaction conditions and increased under the following conditions: (1) at a higher overall concentration of arm chains ([P*]), (2) with a larger degree of polymerization (DP) of the arm chains (arm length), and (3) with a larger ratio (r) of linking agents to P* (core size). In particular, the yields sharply increased in a short time at a higher temperature, in a polar solution, and at a higher complex concentration after the addition of linking agents. These star polymers were then analyzed by multi-angle laser light scattering to determine the weight-average molecular weight (3.8 × 103 to 1.5 × 106), the number of arm chains per molecule (f = 4–63), and the radius of gyration (Rz = 2–22 nm), which also depended on the reaction conditions (e.g., f and Rz increased as [P*], DP, and r increased). Small-angle X-ray scattering analyses of the star polymers showed that they consisted of spheres for which the radius of the microgel core was 2.7 nm. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2245–2255, 2002

Star polymers with end-functionalized arm chains (surface-functionalized star polymers) were synthesized by the in situ linking reaction between ethylene glycol dimethacrylate (linking agent) and an α-end-functionalized linear living poly(methyl methacrylate) in RuCl2(PPh3)3-catalyzed living radical polymerization; the terminal on the surface functionalities included amides, alcohols, amines, and esters. The star polymers were obtained in high yields (75–90%) with initiating systems consisting of a functionalized 2-chloro-2-phenylacetate or -acetamide [FC(O)CHPhCl; F = nPrNH, HOCH2CH2O, Me2NCH2CH2O, or EtO; initiator] and n-Bu3N (additive). The yield was lower with a functionalized 2-bromoisobutyrate [Me2NCH2CH2OC(O)CMe2Br] initiator or with Al(Oi-Pr)3 as an additive. Multi-angle laser light scattering analysis showed that the star polymers had arm numbers of 10–100, radii of gyration of 6–23 nm, and weight-average molecular weights of 1.3 × 105 to 3.0 × 106, which could be controlled by the molar ratio of the linking agent to the linear living polymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1972–1982, 2002

Core-functionalized star-shaped polymers consisting of linear poly(methyl methacrylate) arms and a microgel core with functional groups were found to act as efficient hosts for selective interaction with small organic molecules as guests. For example, star polymer 1 with an amide-functionalized core (Mw = 1.21 × 103; DP(arm) = 100; 71 arms/molecule; −NH−CO− in the core) could interact with benzoic acid, benzyl alcohol, and benzylamine, whereas such interaction was absent with acetophenone, ethyl benzoate, and amylbenzene, indicating that the interaction stems from hydrogen bonding between the host's amide core and the guest. Thus, polymer 1 specifically interacts with benzoic acid in an equimolar mixture of the acid and its ethyl ester. The host−guest interaction is inhibited by polar solvents such as DMF and by acids like CF3CO2H.

A half-metallocene iron iodide complex [Fe(Cp)I(CO)2] induced living radical polymerization of methyl acrylate (MA) in conjunction with an iodide initiator [(CH3)2C(CO2Et)I, 1] and Al(Oi-Pr)3 to give polymers of controlled molecular weights and narrow molecular weight distributions (MWDs) (Mw/Mn < 1.2). With the use of chloride and bromide initiators, the MWDs were broader, whereas the molecular weights were similarly controlled. Other acrylates such as n-butyl acrylate (nBA) and tert-butyl acrylate (tBA) can be polymerized with 1/Fe(Cp)I(CO)2 in the presence of Ti(Oi-Pr)4 and Al(Oi-Pr)3, respectively, to give living polymers. The 1/Fe(Cp)I(CO)2 initiating system is applicable for the synthesis of block and random copolymers of acrylates (MA, nBA, and tBA) and styrene of controlled molecular weights and narrow MWDs (Mw/Mn = 1.2–1.3). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2033–2043, 2002

A highly π-conjugated nanofibrillar network of poly(3-hexyl thiophene) (P3HT) embedded in polydimethylsiloxane (PDMS) elastomer films on SiO2 dielectrics was facilely developed via solution-blending of an ultrasound-assisted dilute P3HT solution with a PDMS precursor followed by spin-casting and curing. In contrast, simple blending without ultrasonication against the dilute P3HT solution yielded large agglomerates in cast films owing to a great difference in solubility parameter (δ) values (P3HT = 9.5 cal(1/2) cm(-3/2), PDMS = 7.3 cal(1/2) cm(-3/2)). In the ultrasound-assisted 0.1 vol % P3HT solutions, the π-conjugated polymer could develop crystalline nanofibrils surrounded by nonpolar hexyl side chains with the same δ value as that of PDMS, yielding homogeneously dispersed 10 wt % loaded P3HT/PDMS blend films. Spun-cast P3HT/PDMS blend films could yield high electrical properties in organic field-effect transistor, including mobilities of up to 0.045 cm(2) V(-1) s(-1) and on/off current ratios of5 × 10(5), as well as excellent environmental stability owing to the outer PDMS layer.

A series of microgel core-functionalized star-shaped polymers were synthesized by the polymer linking reaction method in RuCl2(PPh3)3-catalyzed living radical polymerization. The synthesis was achieved by the polymer linking reaction method; i.e., functionalized divinyl compounds were added in situ to the solution of linear living poly(MMA)s prepared with the Ru(II)-catalyzed living radical polymerization. The functionalized microgel cores thus obtained contained acrylamide and methacrylamide. Also, star polymers with varying densities of the microgel cores were prepared from diacrylamides with various lengths and structures of the spacer, and by changing the relative amounts of MMA (arm length) and divinyl compound (core size) to initiator, a variety of core-functionalized star polymers could be obtained in high yield, These core-functionalized star-shaped polymers have f of 20−640, Mw of 3.3 × 105−1.3 × 107, and Rz of 5−42 nm. These results indicated that the cores carry as many as 440−51 000 amide grou...

Star-shaped polymers that consist of well-defined poly(methyl methacrylate) [poly(MMA)] arms and a microgel core of a divinyl compound were prepared in high yield with the RuCl2(PPh3)3-catalyzed living radical polymerization followed by direct in-situ polymer linking reactions with divinyl compounds. In typical examples, these star-shaped polymers had the arm number (f) of 10−30 and Mw(star) > 105. The following factors were effective in the star-shaped polymer formation: (a) a monofunctionalized chloride initiator; (b) a linking agent with a soft aliphatic or a rigid long aromatic spacer between the two methacryloyl groups.

Over the past half century, low dielectric materials have been intensively researched by ceramic and polymer scientists. However, these materials possess a vast myriad of electrical, thermal, chemical, and mechanical properties that are just as crucial as the name that classifies them. Therefore, in many cases, the applications of low dielectric constant materials are dictated by these other properties, and the choice of low dielectric material may have a tremendous effect on a device’s performance and lifetime.

Photo and temperature cured polymer dielectrics could be fabricated on a gate-patterned glass, with two immiscible polymer precursors, divinyltetramethyldisiloxane-bis(benzocyclobutene) (BCB precursor) and poly(melamine-co-formaldehyde)acrylate (PMFA), which have excellent insulating properties, but show discernible dielectric constants and polarities. On hydrophobic BCB-assisted PMFA blend dielectrics (approximately 400 nm thick), organic field-effect transistors (OFET) and complementary inverters were demonstrated using pentacene and N,N′-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13) as semiconducting channels. The values of field-effect mobilities showed up to 0.33 cm2 V−1 s−1 (for pentacene) and 0.85 cm2 V−1 s−1 (for PTCDI-C13), respectively. In addition, these based complementary inverter was successfully demonstrated with a high voltage gain of ca. 41, specifically, onto the 10 wt% BCB-assisted PMFA dielectric optimized to achieve a hydrophobic and smooth surface by vertically phase-separating the immiscible polymers.

We report on conducting polyaniline (PANI) films doped with a thermally stable polymer dopant, linear ladder-type sulfonated polyphenylsilsesquioxane (S-PPSQ). The PANI/S-PPSQ films exhibited high-temperature stable electrical conductivity. With a heat treatment at 120 °C, the electrical conductivity of conventional PANI films doped with the molecular dopant camphorsulfuric acid (CSA) rapidly decreased to half of its initial value, while that of PANI/S-PPSQ films were relatively unaffected. Moreover, PANI/S-PPSQ films with high electrical conductivity exhibited unusual negative temperature coefficient of resistance (TCR) values above room temperature, in contrast to conventional PANI/CSA films that exhibited positive TCR values. By using a solution blend of PANI/S-PPSQ and PANI/CSA with negative and positive TCR values, respectively, we successfully demonstrated control of TCR behavior. Therefore, PANI/S-PPSQ materials are very promising for organic electronic applications.

Well-defined hybrid polymers consisting of organic polymers grafted from inorganic backbone were synthesized by atom transfer radical polymerization (ATRP). Ladder-like structured polysilsesquioxane functioned as both ATRP initiator and hard inorganic backbone, while the organic polymers grafted were hard styrene and soft n-butyl acrylate. Ladder-like structured poly(chloromethylphenylsilsesquioxane) (LCMPSQ) was synthesized using sequential two-step reactions with (ρ-chloromethyl)phenyltrimethxysilane as a monomer in one bath in the presence of K2CO3 as a base catalyst (M w = 6,000). Obtained LCMPSQ was then used as a multi-functional macroinitiator for graft polymerization of styrene (St) or/and n-butyl acrylate (nBA) monomers via ATRP using a CuCl catalyzed system, which gave three types of hybrid graft polymers: poly(styrene-g-silsesquioxane) (PS-g-PSQ), poly(nBA-g-silsesquioxane) (PnBA-g-PSQ) and poly(styrene-ran-nBA-g-silsesquioxane) (PS/nBA-g-PSQ). The hybrid graft polymers were prepared with vari...

UV crosslinkable sulfonated block copolymers of neopentyl p-styrene sulfonate (NSS) and 2-cinnamoylethyl acrylate (CEA) were synthesized by living radical polymerization. For this, the block copolymers of 2-(trimethylsilyl)ethyl acrylate (TMSEA) and NSS were first synthesized by sequential CuBr catalyzed living radical polymerization with 2-bromopropionate (EBP) initiator and N,N,N′,N′-pentamethylethyleneamine (PMDETA) ligand. Obtained well defined block copolymers (polydispersity

Physical and optical properties of a series of TAC films with different molecular weight synthesized by acetylation of cotton linter have been investigated. The synthesized TACs had fully acetylated structure in which acetic acid contents was about 62%. Dimensional stability, thermal stability, modulus, tensile strength and elongation at break of TAC film were influenced by the molecular weight of base resin and they increased with the molecular weight. TAC films had good transparency as well as optical isotropy. Especially, optical property and moderate physical properties for protective film application in LCD were achieved above the molecular weight of 250 kg/mol.