Charge referencing issues in XPS of insulators as evidenced in the case of Al‐Si‐N thin films

Accurate charge referencing in XPS of insulating specimens is a delicate issue. This difficulty is illustrated in the case of Al‐Si‐N composite thin films deposited by reactive magnetron sputtering with variable composition from pure aluminum nitride to pure silicon nitride. The samples were mounted with Au‐coated metallic clamps. Argon sputter cleaning was required to remove a surface native oxide before analysis. For charge referencing implanted argon atoms from the sputter gas and a small amount of gold re‐deposited from the metallic clamps onto the specimen surface during sputter cleaning were evaluated. For the argon atoms, a surprisingly large chemical shift (～1 eV) and a significant peak broadening (0.6 eV) of the Ar 2p_3/2 photoelectron line were found with varying the Si content of the films. This could be related to chemical and structural changes of the Al‐Si‐N films. Hence implanted argon could not be used for charge referencing of Al‐Si‐N samples. In contrast to the implanted argon, the Au 4f_7/2 line width of the gold re‐deposited onto the sample surface did not depend on the Si content of Al‐Si‐N films. A constant energy shift (～1.2 eV) of the Au 4f_7/2 line as compared with bulk gold was, however, found, which was related to the size of gold particles formed on the insulating films. Therefore gold could be reliably used to study chemical shifts of sample‐relevant species in Al‐Si‐N films, but the absolute binding energies of Al 2p, Si 2p and N 1s photoelectrons could not be determined. Copyright © 2011 John Wiley & Sons, Ltd.     

Amorphous silicon carbonitride thin‐film coatings produced by remote nitrogen microwave plasma chemical vapour deposition using organosilicon precursor

Amorphous silicon carbonitride (a‐SiCN) films were produced by remote nitrogen plasma chemical vapour deposition (RP‐CVD) from bis(dimethylamino)methylsilane precursor. The effect of substrate temperature (T _S) on the kinetics of RP‐CVD, chemical structure, surface morphology and some properties of the resulting films is reported. The T _S dependence of film growth rate implies that RP‐CVD is an adsorption‐controlled process. Fourier transform infrared spectroscopic examination revealed that an increase in T _S from 30 to 400°C involves the elimination of organic moieties from the film and the formation of Si─C and Si─N network structure. The films were characterized in terms of their surface roughness and basic physical and optical properties, such as density and refractive index, respectively. Reasonably good relationships between the structural parameters represented by relative integrated intensity of infrared absorption bands from the Si─C and Si─N bonds (controlled by T _S) and the film properties are determined. Due to their small surface roughness, high density and high refractive index, the a‐SiCN films produced at T _S ≥ 350°C would seem to be useful protective coatings for metals and optical devices.     

Time‐of‐flight SIMS characterization of hydrolysed organofunctional and non‐organofunctional silanes deposited on Al,Zn and Al–43.4Zn–1.6Si alloy‐coated steel

In this paper Al, Zn and Al–43.4Zn–1.6Si (AlZn) alloy‐coated steel have been treated with the organofunctional silane γ‐mercaptopropyltrimethoxysilane (γ‐MPS) and the non‐organofunctional silane 1,2‐bis(triethoxysilyl)ethane (BTSE). Also, a two‐step treatment of metal substrates was performed: the metal substrates were treated with the BTSE silane followed by a γ‐MPS treatment. The influence of metal substrate and the pH value of the silane film properties were investigated using time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). The results show that the BTSE silane is fully hydrolysed but the γ‐MPS silane is not. The presence of negative ions of the type HSi_xO_y^? indicates that both types of silane films are highly cross‐linked via Si–O–Si bonds. The two‐step treatment gave a γ‐MPS silane layer on top of the BTSE silane layer but the thickness of the total silane film become thinner than for a single BTSE film, indicating that some of the BTSE is dissolved during the γ‐MPS deposition step. Furthermore, the ToF‐SIMS results show that the thiol group of the γ‐MPS silane is oxidized. Finally, no major influence, either in the positive or the negative mass spectra, from the different metal substrates could be detected for the silane films investigated. Copyright © 2003 John Wiley & Sons, Ltd.     

Difunctionalized {closo‐1‐CB11} Clusters: 1‐ and 2‐Amino‐12‐ethynylcarba‐closo‐dodecaborates

Carba‐closo‐dodecaborate anions with two functional groups have been synthesized via a simple two‐step procedure starting from monoamino‐functionalized {closo‐1‐CB₁₁} clusters. Iodination at the antipodal boron atom provided access to [1‐H₂N‐12‐I‐closo‐1‐CB₁₁H₁₀]^? ( 1 a ) and [2‐H₂N‐12‐I‐closo‐1‐CB₁₁H₁₀]^? ( 2 a ), which have been transformed into the anions [1‐H₂N‐12‐RC?C‐closo‐1‐CB₁₁H₁₀]^? (R=H ( 1 b ), Ph ( 1 c ), Et₃Si ( 1 d )) and [2‐H₂N‐12‐RC?C‐closo‐1‐CB₁₁H₁₀]^? (R=H ( 2 b ), Ph ( 2 c ), Et₃Si ( 2 d )) by microwave‐assisted Kumada‐type cross‐coupling reactions. The syntheses of the inner salts 1‐Me₃N‐12‐RC?C‐closo‐1‐CB₁₁H₁₀ (R=H ( 1 e ), Et₃Si ( 1 f )) and 2‐Me₃N‐12‐RC?C‐closo‐1‐CB₁₁H₁₀ (R=H ( 2 e ), Et₃Si ( 2 f )) are the first examples for a further derivatization of the new anions. All {closo‐1‐CB₁₁} clusters have been characterized by multinuclear NMR and vibrational spectroscopy as well as by mass spectrometry. The crystal structures of Cs 1 a , [Et₄N] 2 a , K 1 b , [Et₄N] 1 c , [Et₄N] 2 c , 1 e , and [Et₄N][1‐H₂N‐2‐F‐12‐I‐closo‐1‐CB₁₁H₉]?0.5 H₂O ([Et₄N ]4 a ?0.5 H₂O) have been determined. Experimental spectroscopic data and especially spectroscopic data and bond properties derived from DFT calculations provide some information on the importance of inductive and resonance‐type effects for the transfer of electronic effects through the {closo‐1‐CB₁₁} cage.     

Photocurrent Enhancement of Dye‐Sensitized Solar Cells owing to Increased Dye‐Adsorption onto Silicon‐Nanoparticle‐Coated Titanium‐Dioxide Films

The inverse‐micellar preparation of Si nanoparticles (Nps) was improved by utilizing sodium naphthalide. The Si Nps were subsequently functionalized with 4‐vinylbenzoic acid for their attachment onto TiO₂ films of dye‐sensitized solar cells (DSSCs). The average diameter of the COOH‐functionalized Si (Si? COOH) Nps was 4.6(±1.7) nm. Depth profiling by secondary‐ion mass spectrometry revealed that the Si Nps were uniformly attached onto the TiO₂ films. The number of Ru^II dye molecules adsorbed onto a TiO₂ film that was treated with the Si? COOH Nps was 42 % higher than that on the untreated TiO₂ film. As a result, DSSCs that incorporated the Si? COOH Nps exhibited higher short‐circuit photocurrent density and an overall energy‐conversion efficiency than the untreated DSSCs by 22 % and 27 %, respectively. This enhanced performance, mostly owing to the intramolecular charge‐transfer to TiO₂ from the dye molecules that were anchored to the Si? COOH Nps, was confirmed by comparing the performance with two different Ru^II–bipyridine dyes (N719 and N749).     

The high‐temperature tribological properties of Si‐DLC films

The tribological properties of Silicon‐containing diamond‐like‐carbon (Si‐DLC) films, deposited by magnetron sputtering Si target in methane/argon atmosphere, were studied in comparison with diamond‐like‐carbon (DLC) films. The DLC films disappeared because of the oxidation in the air at 500 °C, whereas the Si‐DLC films still remained, implying that the addition of Si improved significantly the thermal stability of DLC films. Retarded hydrogen release from DLC film at high temperature and silicon oxide on the surface might have contributed to lower friction coefficient of the Si‐DLC films both after annealing treatment and in situ high‐temperature environment. Copyright © 2012 John Wiley & Sons, Ltd.     

CrB‐Type Phases in the Tb‐Zr‐Al‐Si System

The crystal structures of Tb(Al_0.15Si_0.85), (Tb_0.70Zr_0.30)(Al_0.17Si_0.83) and Zr(Al_0.22Si_0.78) have been refined from single‐crystal X‐ray diffraction data. The three compounds crystallize with CrB‐type structures (Pearson symbol oS8, space group Cmcm): Tb(Al_0.15Si_0.85): a = 4.2715(5), b = 10.5595(15), c = 3.8393(5) Å; (Tb_0.70Zr_0.30)(Al_0.17Si_0.83): a = 4.163(2), b = 10.423(5), c = 3.8543(18) Å; Zr(Al_0.22Si_0.78): a = 3.7824(6), b = 10.0164(16), c = 3.7795(5) Å. The existence of a significant CrB‐type solid solution in the quaternary system Tb‐Zr‐Al‐Si, based on the ternary compound Tb(Al_0.15Si_0.85) and extending toward the solid solution based on the binary compound ZrSi in the Zr‐Al‐Si system, cannot be excluded.     

Mesostructured Dye‐Doped Titanium Dioxide for Micro‐Optoelectronic Applications

Optically transparent, mesostructured titanium dioxide thin films were fabricated using an amphiphilic poly(alkylene oxide) block copolymer template in combination with retarded hydrolysis of a titanium isopropoxide precursor. Prior to calcination, the films displayed a stable hexagonal mesophase and high refractive indices (1.5 to 1.6) relative to mesostructured silica (1.43). After calcination, the hexagonal mesophase was retained with surface areas >300 m² g^?1. The dye Rhodamine 6G (commonly used as a laser dye) was incorporated into the copolymer micelle during the templating process. In this way, novel dye‐doped mesostructured titanium dioxide films were synthesised. The copolymer not only directs the film structure, but also provides a solubilizing environment suitable for sustaining a high monomer‐to‐aggregate ratio at elevated dye concentrations. The dye‐doped films displayed optical thresholdlike behaviour characteristic of amplified spontaneous emission. Soft lithography was successfully applied to micropattern the dye‐doped films. These results pave the way for the fabrication and demonstration of novel microlaser structures and other active optical structures. This new, high‐refractive index, mesostructured, dye‐doped material could also find applications in areas such as optical coatings, displays and integrated photonic devices.     

Synthesis and properties of Q‐silicon crosslinked siloxane networks: H3PO4‐catalyzed sol–gel dehydration/crosslinking of α,ω‐bis(hydroxy)oligodimethylsiloxanes with tetrakis(hydroxydimethylsiloxy)silane

Six silicate‐crosslinked oligodimethylsiloxane thin films were prepared by the phosphoric acid (1 mol %) catalyzed condensation of α,ω‐bis(hydroxy)oligodimethylsiloxane (P) and tetrakis(hydroxydimethylsiloxy)silane (Q). Other acid catalysts were evaluated. P and Q were prepared by the Pd‐catalyzed oxidation of the corresponding Si? H compounds with water. The starting materials were characterized by IR and ¹H, ¹³C, and ²⁹Si NMR. A thermal cure was achieved with H₃PO₄ in 24 h and with poly(phosphoric acid) in 3 h at 110–120 °C. Dynamic mechanical analysis was used to determine the glass‐transition temperatures and to evaluate the mechanical properties of the films. Their thermal stabilities (≥300 °C) in air and N₂ were determined by thermogravimetric analysis. Small amounts of non‐crosslinked P were recovered from the films by Soxhlet extractions with CH₂Cl₂ and analyzed by IR, gel permeation chromatography, and ²⁹Si NMR. The crosslink densities were evaluated by the CH₂Cl₂ absorption capacities of the films. The surface properties of the films were determined by static and dynamic contact‐angle measurements. Electrochemical impedance spectroscopy was carried out to evaluate the corrosion‐protective properties of the coatings on mild steel as a function of the exposure time to 0.5 N NaCl. The biofoul‐release properties of the films were evaluated with sporelings from mature Ulva linza plants and barnacles. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2237–2247, 2006     

Synthesis and characterization of new soluble polyamides from 1,1‐bis[4‐(4‐carboxyphenoxy)phenyl]‐4‐tert‐butylcyclohexane and various diamines

A new dicarboxylic acid monomer, 1,1‐bis[4‐(4‐carboxyphenoxy)phenyl]‐4‐tert‐butylcyclohexane, bearing a pendent tert‐butylcyclohexylidene group was prepared in three steps from 4‐tert‐butylcyclohexanone. The monomer was reacted with various diamines to produce a series of new polyamides with triphenyl phosphite and pyridine as condensing agents. These polyamides were produced with inherent viscosities of 0.74 to 1.02 dL g⁻¹. All the polymers were characterized by X‐ray diffraction that revealed this amorphous nature. These polymers exhibited excellent solubility in a variety of solvents. Almost all the polymers could be dissolved in N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide, dimethyl sulfoxide, pyridine, and even in tetrahydrofuran and cyclohexanone. These polymers showed glass‐transition temperatures between 223 and 256 °C and decomposition temperatures at 10% weight loss ranging from 468 to 491 °C and 469 to 498 °C in nitrogen and air atmospheres, respectively. Transparent, tough, and flexible films of these polymers were cast from the DMAc solutions. These polymer films had tensile strengths ranging from 76 to 99 MPa, elongations at break from 7 to 19%, and initial moduli from 2.1 to 2.7 GPa. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 797–803, 2000     

Reaction of N‐Heterocyclic Silylenes with Thioketone: Formation of Silicon–Sulfur Three (Si‐C‐S)‐ and Five (Si‐C‐C‐C‐S)‐Membered Ring Systems

Three‐ and five‐membered rings that bear the (Si‐C‐S ) and (Si‐C‐C‐C‐S ) unit have been synthesized by the reactions of L SiCl ( 1 ; L =PhC(NtBu)₂) and L′ Si ( 2 ; L′ =CH{(C?CH₂)(CMe)(2,6‐iPr₂C₆H₃N)₂}) with the thioketone 4,4′‐bis(dimethylamino)thiobenzophenone. Treatment of 4,4′‐bis(dimethylamino)thiobenzophenone with L SiCl at room temperature furnished the [1+2]‐cycloaddition product silathiacyclopropane 3 . However, reaction of 4,4′‐bis(dimethylamino)thiobenzophenone with L′ Si at low temperature afforded a [1+4]‐cycloaddition to yield the five‐membered ring product 4 . Compounds 3 and 4 were characterized by NMR spectroscopy, EIMS, and elemental analysis. The molecular structures of 3 and 4 were unambiguously established by single‐crystal X‐ray structural analysis. The room‐temperature reaction of 4,4′‐bis(dimethylamino)thiobenzophenone with L′ Si resulted in products 4 and 5 , in which 4 is the dearomatized product and 5 is formed under the 1,3‐migration of a hydrogen atom from the aromatic phenyl ring to the carbon atom of the C? S unit. Furthermore, the optimized structures of probable products were investigated by using DFT calculations.     

Highly stable electrochromic polyamides based on N,N‐bis(4‐aminophenyl)‐N′,N′‐bis(4‐tert‐butylphenyl)‐1,4‐phenylenediamine

A new triphenylamine‐containing aromatic diamine monomer, N,N‐bis(4‐aminophenyl)‐N′,N′‐bis(4‐tert‐butylphenyl)‐1,4‐phenylenediamine, was synthesized by an established synthetic procedure from readily available reagents. A novel family of electroactive polyamides with di‐tert‐butyl‐substituted N,N,N′,N′‐tetraphenyl‐1,4‐phenylenediamine units were prepared via the phosphorylation polyamidation reactions of the newly synthesized diamine monomer with various aromatic or aliphatic dicarboxylic acids. All the polymers were amorphous with good solubility in many organic solvents, such as N‐methyl‐2‐pyrrolidinone (NMP) and N,N‐dimethylacetamide, and could be solution‐cast into tough and flexible polymer films. The polyamides derived from aromatic dicarboxylic acids had useful levels of thermal stability, with glass‐transition temperatures of 269–296 °C, 10% weight‐loss temperatures in excess of 544 °C, and char yields at 800 °C in nitrogen higher than 62%. The dilute solutions of these polyamides in NMP exhibited strong absorption bands centered at 316–342 nm and photoluminescence maxima around 362–465 nm in the violet‐blue region. The polyamides derived from aliphatic dicarboxylic acids were optically transparent in the visible region and fluoresced with a higher quantum yield compared with those derived from aromatic dicarboxylic acids. The hole‐transporting and electrochromic properties were examined by electrochemical and spectro‐electrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium‐tin oxide‐coated glass substrate exhibited two reversible oxidation redox couples at 0.57–0.60 V and 0.95–0.98 V versus Ag/AgCl in acetonitrile solution. The polyamide films revealed excellent elcterochemical and electrochromic stability, with a color change from a colorless or pale yellowish neutral form to green and blue oxidized forms at applied potentials ranging from 0.0 to 1.2 V. These anodically coloring polymeric materials showed interesting electrochromic properties, such as high coloration efficiency (CE = 216 cm²/C for the green coloring) and high contrast ratio of optical transmittance change (ΔT%) up to 64% at 424 nm and 59% at 983 nm for the green coloration, and 90% at 778 nm for the blue coloration. The electroactivity of the polymer remains intact even after cycling 500 times between its neutral and fully oxidized states. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2330–2343, 2009     

Equilibrium Formation of Stable All‐Silicon Versions of 1,3‐Cyclobutanediyl

Main group analogues of cyclobutane‐1,3‐diyls are fascinating due to their unique reactivity and electronic properties. So far only heteronuclear examples have been isolated. Here we report the isolation and characterization of all‐silicon 1,3‐cyclobutanediyls as stable closed‐shell singlet species from the reversible reactions of cyclotrisilene c‐Si₃Tip₄ (Tip=2,4,6‐triisopropylphenyl) with the N‐heterocyclic silylenes c‐[(CR₂CH₂)(NtBu)₂]Si: (R=H or methyl) with saturated backbones. At elevated temperatures, tetrasilacyclobutenes are obtained from these equilibrium mixtures. The corresponding reaction with the unsaturated N‐heterocyclic silylene c‐(CH)₂(NtBu)₂Si: proceeds directly to the corresponding tetrasilacyclobutene without detection of the assumed 1,3‐cyclobutanediyl intermediate.     

Synthesis and characterization of UV‐curable ladder‐like polysilsesquioxane

Various ladder‐like structured poly(phenyl‐co‐methacryl silsesquioxane)s (LPMSQ)s with high molecular weight (M_w = 10,000 ～ 40,000) were synthesized by direct hydrolysis and polymerization in the presence of base catalyst at 25 °C. Synthesized LPMSQs mainly showed ladder‐like structure and photo‐cure reaction by 100 mW/cm² (360 nm) for 10 s without any photo‐cure initiators. Chemical composition and structural analysis of the obtained LPMSQs were characterized using ¹H NMR, ²⁹Si NMR, Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and X‐ray diffraction (XRD). Physical properties of LPMSQs before and after photcuring were analyzed by Nanoindentation. Surface modulus increased to 8GPa and hardness of thin films increased from 100 to 400 MPa. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Die Hydroaluminierung von 1,1,4,4‐Tetramethyl‐2,3‐diazabutadien mit Dialkylaluminiumhydriden – Synthese von Dialkylaluminiumhydrazoniden

The Hydroalumination of 1,1,4,4‐Tetramethyl‐2,3‐diazabutadiene by Dialkylaluminium Hydrides – Synthesis of Dialkylaluminium Hydrazonides 1,1,4,4‐Tetramethyl‐2,3‐diazabutadiene reacted with dimethylaluminium hydride by hydroalumination of only one C=N double bond. The hydrazone derivative [Me₂Al–N(CHMe₂)–N=CMe₂]₂ ( 1 ) was formed which gave a dimer possessing a six‐membered Al₂N₄ heterocycle. The hydroalumination of both C=N double bonds was not observed. Also an excess of di(tert‐butyl)‐ or bis(trimethylsilylmethyl)aluminium hydride afforded only the product of a single hydroalumination step, a second dialkylaluminium hydride molecule was attached via a coordinative interaction between its central aluminium atom and the nitrogen atom of the C=N double bond and in addition via a 3 c‐2 e Al–H–Al bond. Compounds [(Me₃C)₂Al][(Me₃C)₂AlH]N(CHMe₂)NCMe₂ ( 2 ) and [(Me₃SiCH₂)₂Al][(Me₃SiCH₂)₂AlH]N(CHMe₂)NCMe₂ ( 3 ) were formed which have five‐membered Al₂N₂H heterocycles. Thermolysis of 2 gave by C–H activation compound [(Me₃C)₂Al]₂[CH₂C(Me)=N–]₂ ( 4 ) in trace amounts which possesses two anellated AlN₂C₂ rings with a common N–N bond. In contrast, the thermal decomposition of 3 yielded by the cleavage of the N–N bond a dimeric dialkylaluminium methylideneamide ( 5 ) which has two intact C=N double bonds. Up to now our attempts to insert a C=N double bond into an Al–C bond remained unsuccessful, and only the formation of an adduct [(Me₃C)₃Al(–N=CMe₂)₂] ( 6 ) was observed upon treatment of tri(tert‐butyl)aluminium with the diazabutadiene derivative.     

Bifunktionalisierte 1 H‐Phosphiren‐ und g1‐1‐Phosphaallen‐Wolframkomplexe

Bifunctionalized 1 H‐Phosphirene and g¹‐1‐Phosphaallene Tungsten Complexes The tungsten(0) complex [{(Me₃Si)₂HCPC(Ph)=N}W(CO)₅] 1 reacts upon heating with acetylene derivatives 2 a–d in toluene to form benzonitrile and the complexes [{(Me₃Si)₂HCPC(R)=COEt} · W(CO)₅] 5 a–d ( 5 a : R = SiMe₃; 5 b : R = SiPh₃; 5 c : R = SnMe₃; 5 d : R = SnPh₃) and [{(Me₃Si)₂HCP=C=C(OEt)R} · W(CO)₅] 6 a, b ( 6 a : R = SnMe₃; 6 b : R = SnPh₃), which have been isolated by chromatography; complexes 5 c and 6 a have been characterized as mixtures. Spectroscopic and mass spectrometric data are discussed. The crystal structure of the compound 5 a was determined by X‐ray single crystal structure analysis ( 5 a : space group P2₁/n, Z = 4, a = 977.6(2) pm, b = 1814.6(4) pm, c = 1628.0(4) pm, β = 93.95(2)°).     

Luminescent Amphiphilic 2,6‐Bis(1‐alkylpyrazol‐3‐yl)pyridyl Platinum(II) Complexes: Synthesis,Characterization, Electrochemical,Photophysical, and Langmuir–Blodgett Film Formation Studies

Two series of novel platinum(II) 2,6‐bis(1‐alkylpyrazol‐3‐yl)pyridyl (N5Cn) complexes, [Pt(N5Cn)Cl][X] ( 1 – 9 ) and [Pt(N5Cn)(C?CR)][X] ( 10 – 13 ) (X=trifluoromethanesulfonate (OTf) or PF₆; R=C₆H₅, C₆H₄‐p‐CF₃ and C₆H₄‐p‐N(C₆H₅)₂), with various chain lengths of the alkyl groups on the nitrogen atom of the pyrazolyl units have been successfully synthesized and characterized. Their electrochemical and photophysical properties have been studied. Some of their molecular structures have also been determined by X‐ray crystallography. Two amphiphilic platinum(II) 2,6‐bis(1‐tetradecylpyrazol‐3‐yl)pyridyl (N5C14) complexes, [Pt(N5C14)Cl]PF₆ ( 7 ) and [Pt(N5C14)(C?CC₆H₅)]PF₆ ( 13 ), were found to form stable and reproducible Langmuir–Blodgett (LB) films at the air–water interface. The characterization of such LB films has been investigated by the study of their surface pressure–area (π–A) isotherms, UV/Vis spectroscopy, XRD, X‐ray photoelectron spectroscopy (XPS), FTIR, and polarized IR spectroscopy. The luminescence property of 13 in LB films has also been studied.     

Novel amorphous perfluorocopolymeric system: Copolymers of perfluoro‐2‐methylene‐1,3‐dioxolane derivatives

Perfluorotetrahydro‐2‐methylene‐furo[3,4‐d][1,3]dioxole (monomer I ) and perfluoro‐2‐methylene‐4‐methoxymethyl‐1,3‐dioxolane (monomer II ) are soluble in perfluorinated or partially fluorinated solvents and readily polymerize in solution or in bulk when initiated by a free‐radical initiator, perfluorodibenzoyl peroxide. The copolymerization parameters have been determined with in situ ¹⁹F NMR measurements. The copolymerization reactivity ratios are r _I = 1.80 and r _II = 0.80 in 1,1,2‐trichlorotrifluoroethane at 41 °C and r _I = 0.97 and r _II = 0.85 for the bulk polymerization. These data show that this copolymerization pair has a good copolymerization tendency and yields nearly ideal random copolymers. The copolymers have only one glass‐transition temperature from 101 to 168 °C, depending on the copolymer compositions. Melting endotherms have not been observed in their differential scanning calorimetry traces, and this indicates that all the copolymers with different compositions are completely amorphous. These copolymers are thermally stable (the initial decomposition temperatures are higher than 350 °C under an N₂ atmosphere) and have low refractive indices and high optical transparency from UV to near‐infrared. Copolymer films prepared by casting were flexible and tough. These properties make the copolymers ideal candidates as optical and electrical materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1613–1618, 2006     

In Situ Electrochemical Synthesis of Oriented and Defect‐Free AEL Molecular‐Sieve Films Using Ionic Liquids

Simply preparing oriented and defect‐free molecular‐sieve films have been a long‐standing challenge both in academia and industry. Most of the early works focus on the careful and multiple controls of the seeds layer or synthesis conditions. Herein, we report a one‐step in situ electrochemical ionothermal method that combines a controllable electric field with ionic liquids. We demonstrate that an in‐plane oriented and defect‐free AEL (one molecular‐sieve framework type) molecular‐sieve film was obtained using an Al electrode as the Al source. The excellent corrosion‐resistant performance of the film makes this technology promising in multiple applications, such as anti‐corrosion coatings.     

Zur Benennung von Verbindungen im Si‐Al‐O‐N‐System

Die Übersetzung basiert auf der „Terminology for Compounds in the Si‐Al‐O‐N System“ der Commission on High Temperature Materials and Solid State Chemistry der Inorganic Chemistry Division der International Union of Pure and Applied Chemistry, veröffentlicht in Pure Appl. Chem. 1999 , 71, 1765–1769. Das Original wurde von R. Metselaar, Technische Universiteit Eindhoven (Niederlande) und D. S. Yan, Academia Sinica, Shanghai (China) für die Veröffentlichung vorbereitet.