聚合物结构对聚合物网络稳定液晶薄膜电光性能的影响

用带有联苯结构的双丙烯酸酯和单丙烯酸酯作为单体,采用紫外光引发聚合诱导相分离法制备了聚合物网络稳定液晶(PSLC)薄膜。研究了不同液晶含量、固化时间、单体结构、取向层对PSLC膜电光性能的影响。结果表明,随着液晶含量的增加,样品的关态透光率(TOFF)随之增大,驱动电压则呈减小趋势;相对而言,随固化时间的增加,样品的TOFF则降低。在PI作取向层时,由双丙烯酸酯单体制备的样品表现出了较高的TOFF,而由单丙烯酸酯单体制得的样品,因其聚合物网络结构的不稳定性,在较低电压情况下就出现了"变形"的电光曲线。     

Conformal polymeric thin films by low-temperature rapid initiated chemical vapor deposition (iCVD) using tert-butyl peroxybenzoate as an initiator

Conformal poly(cyclohexyl methacrylate) (pCHMA) thin films were synthesized via initiated chemical vapor deposition (iCVD), with tert-butyl peroxybenzoate (TBPOB) as the initiator, representing the first time that TBPOB has been used as an initiator for iCVD synthesis. Using TBPOB instead of tert-butyl peroxide (TBPO), the rate of iCVD film growth increased by a factor of up to seven at comparable conformality and lower the filament temperature from 257 to 170 °C at a comparable deposition rate of 3 nm/min. The conformal deposition of functional thin films is desired for applications including microfluidics, medical devices and membranes. Lower filament temperatures reduce the heat load to the deposition surface and thus are advantageous for polymeric substrates that are temperature sensitive or monomers that decompose at high temperatures. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results demonstrate the similarity of the TBPOB- to the TBPO-initiated pCHMA main chains. However, the aromatic group in TBPOB provided a unique spectral signature of the polymer chain end group in the FTIR and the peak intensity increased with increase of filament temperature. Scanning electron micrographs (SEMs) revealed that the pCHMA coatings are conformal over non-planar structures; however, at identical process conditions, TBPO-initiated films showed a slightly better conformality due to the lower sticking coefficient of TBPO. At a monomer partial pressure of 0.45, TBPOB has a sticking coefficient value of 0.1188 ± 0.0092, which is ～3 times as high as that of TBPO (0.0413 ± 0.0058). The step coverage is insensitive to filament temperature if the surface concentration of the monomer is fixed.     

Creation of biofunctionalized micropatterns on poly(methyl methacrylate) by single-step phase separation method

In this study, the polymer thin films containing micropatterns and biological functionalities were created by one-step procedure. The adjustable compositions among poly(methyl methacrylate) (PMMA), solvents, nonsolvent, and additional macromolecules formed the polymer thin films with different diameters ranging from 5 to 37 μm. The influences of topographical and chemical cues were investigated by directly cultivating L-929 fibroblasts on the prepared samples. The results revealed the predominant effect of surface topography that the cell density of L-929 fibroblasts increased proportionally with the average diameter of microconcaves. The cell number raised significantly on the PMMA thin films containing type I collagen and dopamine, with or without microstructures. On the other hand, the addition of bovine serum albumin in PMMA limited the growth of cells. The surface chemical composition and cell responses were evaluated by electron spectroscopy for chemical analysis (ESCA), viability assay, and immunostaining, respectively. This work proposed a simple and effective approach to incorporate the biological functions and surface topography simultaneously onto surface of materials that provided further applications for biomedical materials.     

Controlled preparation of macroporous TiO2 films by photo polymerization-induced phase separation method and their photocatalytic performance

TiO₂ films with controlled macroporous structures have been prepared from the precursor solution containing photo monomer pentaerythritol tetraacrylate by a photo polymerization-induced phase separation method (PIPS) in the absence of any surfactant and colloidal templates. The gel TiO₂ film deposited from the precursor solution by dip-coating was irradiated with ultraviolet light for some time. During the irradiation process, the polymerization of the photo monomer was induced, which resulted in the phase separation in the film system. After the reaction, two phases existed in the film, one was the emerging polymer rich phase, another was the residual monomer-TiO₂ oligomer rich phase. After heat-treatment at 600 °C, the entire polymer decomposed and a well-defined interconnected macroporous TiO₂ films could be obtained. X-ray diffraction, scanning electron microscopy, atomic force microscopy, thermogravimetric and differential thermal analysis were used to characterize the macroporous TiO₂ films. The results showed that the macroporous texture could be tuned by changing the composition of the precursor solution. The solvent evaporation was controlled by the addition of polyvinylpyrrolidone. Highly macroporous TiO₂ films prepared by the PIPS method exhibited much higher photocatalytic activity for the decomposition of methylene blue dye than the dense TiO₂ film.     

Study of PEDOT conductive polymer films by admittance measurements

In this paper we propose the use of a microwave technique to measure the conductivity of poly(3,4-ethylenedioxythiophene) (PEDOT) films. The PEDOT layers were prepared by electropolymerization from aqueous solutions using both poly(sodium 4-styrene sulphonate) (NaPSS) and sodium dodecyl sulphate (NaDS) acting as monomer solubilizer and dopant for the polymer. The conductive properties of a series of samples produced under different synthesis conditions and characterized by different structures have been investigated by microwave measurements in the frequency range from 40 MHz to 40 GHz by using a Corbino disc geometry. Such technique allows to estimate the mean conductivity of the polymer samples overcoming the limitations of the measuring configurations typically imposed by the conventional d.c. measurements. The morphology of PEDOT films and the structure of polymer chains were studied by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. The correlated morphological, structural and microwave analysis enabled us to evidence several factors that affect the macroscopic scale conductivity of the polymer sample films and to identify the conditions for preparation of PEDOT films with functional properties relevant to technological applications.     

Controlled formation of thin polymer films by electron irradiation

Thin polymer films have been produced by electron bombardment in the presence of the monomer, and their electrical properties have been determined using both planar and sandwich-type structures. The possibility of introducing impurity metal atoms into the polymer structure has also been studied, using silver as the impurity in organosilicon polymer films.It is shown that the conditions of electron bombardment have a pronounced effect on the electrical conductivity. For very high beam currents, the film is highly disordered and exhibits electrical conductivity in certain polymers based on silacyclobutane. The electrical conductivity can be increased greatly by doping with silver to introduce additional impurity levels into the organic structure.     

单体BAB6和手性剂含量对聚合物网络稳定液晶电光性能的影响

采用单体4,4′-二[6-(丙烯酰氧基)己氧基]联苯(BAB6)和胆甾相液晶混合光固化,制得聚合物网络稳定液晶(PSLC)薄膜。利用紫外可见分光光度计、响应时间测试装置和扫描电子显微镜(SEM),研究了单体BAB6和手性剂质量分数对PSLC薄膜电光性能和网络微观形貌的影响。结果表明,随着BAB6质量分数增加,PSLC薄膜的聚合物网眼尺寸变小,透过率降低,饱和电压增加,响应时间缩短;随着手性剂质量分数增加,聚合物网眼尺寸缩小,液晶畴变小,驱动电压增加,响应时间进一步下降。当液晶∶单体∶手性剂的质量比为100∶5∶10时,制得了电光性能优良,响应时间为2ms的PSLC薄膜。     

Chemical vapor phase polymerization deposition of layer-ordered conducting polymer nanostructure for hole injection layer

Layer-ordered and ultrathin films of conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT) was prepared through a chemical vapor phase polymerization method. The chemical polymerization of 3, 4-ethylenedioxythiophene monomer was initiated in as-prepared oxidant LB films,and PEDOT nanofilms with layer-ordered structure was constructed. UV-Vis absorption spectrum and Fourier transform infrared spectroscopy was used to confirm an interface polymerization of PEDOT in as-prepared LB films. The results of X-ray diffraction and secondary ion mass spectrometry revealed that conductive PEDOT ultrathin layers were well located at different planes of LB films. The film deposition surface pressure and chemical polymerization time of PEDOT monomer in as-prepared LB films showed distinct influence on surface morphology and conductive performance of the polymerized PEDOT LB films. This layer-ordered conducting polymer ultrathin films was deposited on ITO surface as hole injection layer for organic light-emitting diodes, and the luminescence performance of devices was improved as well.     

Scanning thermal lithography of tailored tert-butyl ester protected carboxylic acid functionalized (meth)acrylate polymer platforms

In this paper, we report on the development of tailored polymer films for high-resolution atomic force microscopy based scanning thermal lithography (SThL). In particular, full control of surface chemical and topographical structuring was sought. Thin cross-linked films comprising poly(tert-butyl methacrylate) (MA(20)) or poly(tert-butyl acrylate) (A(20)) were prepared via UV initiated free radical polymerization. Thermogravimetric analysis (TGA) and FTIR spectroscopy showed that the heat-induced thermal decomposition of MA(20) by oxidative depolymerization is initially the primary reaction followed by tert-butyl ester thermolysis. By contrast, no significant depolymerization was observed for A(20). For A(20) and MA(20) (at higher temperatures and/or longer reaction times) the thermolysis of the tert-butyl ester liberates isobutylene and yields carboxylic acid groups, which react further intramolecularly to cyclic anhydrides. The values of the apparent activation energies (E(a)) for the thermolysis were calculated to be 125 ± 13 kJ mol(-1) and 116 ± 7 kJ mol(-1) for MA(20) and A(20), respectively. Both MA(20) and A(20) films showed improved thermomechanical stability during SThL compared to non cross-linked films. Carboxylic acid functionalized lines written by SThL in A(20) films had a typically ~10 times smaller width compared to those written in MA(20) films regardless of the tip radius of the heated probe and did not show any evidence for thermochemically or thermomechanically induced modification of film topography. These observations and the E(a) of 45 ± 3 kJ mol(-1) for groove formation in MA(20) estimated from the observed volume loss are attributed to oxidative thermal depolymerization during SThL of MA(20) films, which is considered to be the dominant reaction mechanism for MA(20). The smallest line width values obtained for MA(20) and A(20) films with SThL were 83 ± 7 nm and 21 ± 2 nm, whereas the depth of the lines was below 1 nm, respectively.     

微-纳米复合结构ZnO薄膜的制备及其浸润性的研究

采用水浴法,在ITO玻璃表面生长出具有微-纳复合结构的ZnO薄膜,分别用高分辨扫描电镜(SEM)和接触角测量仪对其表面形貌和表面的浸润性进行了表征。实验结果表明,随着HF使用量的增加,ZnO薄膜的微观结构由球形逐渐过渡到花瓣状,使用三甲基氯硅烷修饰后,其表面接触角由(70±0.5)°逐渐增大到(141.5±0.5)°,同时也对氢氟酸(HF)对ZnO生长的调控机理进行了探讨。     

含铁聚合物薄膜的制备、结构和性能

采用等离子体增强金属有机化合物化学气相沉积（PEMOCVD）工艺制备含铁聚合物薄膜。考察了偏压、源物加热电压对膜的沉积速率及膜中Fe的填充系数的影响。用IR，XPS，TEM和TED对膜的组成和结构进行了分析，表明薄膜具有Fe团簇镶嵌在聚合物基质中的杂混结构特征。对薄膜的光学、电学及湿敏特性进行了研究，证明膜的填充系数对膜的结构和性能都有很大的影响。该薄膜具有较好的湿敏性能。     

Electrochemical Formation of Polypyrrole-carboxymethylcellulose Conducting Polymer Composite Films

1.IntroductionConjugated polymers such as polypyrrole(PPY),polyaniline,polythiophene and polyphenylene etc.whichexhibit significant level of electrical conductivity andhence are termed as conducting polymers,have gotversatile promising applications in the field of energystorage[1],sensors[2],electronic and optical devices[3]andso on.Many researches have been conducted to pro-duce composites or blends of conducting polymer filmswith some insulating polymers in order to overcome thedrawbacks su…     

Stretching and distortion of a photosensitive polymer film by surface plasmon generated near fields in the vicinity of a nanometer sized metal pin hole

Here we demonstrate how a surface plasmon (SP) generated near field pattern in the vicinity of a nano-scale pin hole can be used to generate reversible topography changes in a photosensitive polymer film above the opening. This can be achieved by simply changing the polarization state of the plasmon generating incoming light. In the case of linear polarization, the near field intensity pattern causes the film to laterally expand/contract according to the direction of the polarization. For circular polarization, two pronounced rims corresponding to maxima in the topography are observed. In all cases, the topographical variation is in close agreement with the SP intensity distribution computed from finite difference time domain simulation. Our results demonstrate the versatility of using SP near fields to imprint a variety of structures into photosensitive polymer films using only a single metallic mask.     

Electrochemical synthesis and characterization of chloride doped polyaniline

Chloride doped polyaniline conducting polymer films have been prepared in a protic acid medium (HCl) by potentiodynamic method in an electrochemical cell and studied by cyclic voltammetry and FTIR techniques. The FTIR spectra confirmed Cl^- ion doping in the polymers. The polymerization rate was found to increase with increasing concentration of aniline monomer. But the films obtained at high monomer concentration were rough having a nonuniform flaky polyaniline distribution. Results showed that the polymerization rate did not increase beyond a critical HCl concentration. Cyclic voltammetry suggested that, the oxidation-reduction current increased with an increase in scan rate and that the undoped polyaniline films were not hygroscopic whereas chloride doped polyaniline films were found to be highly hygroscopic.     

Structure and morphology of phenylsilanes polymer films synthesized by the plasma polymerization method

Phenylsilanes were deposited by r.f. glow discharge to investigate the relationship between the synthesis conditions (r.f. power, synthesis time and monomer) and the structure and morphology of plasma-polymerized films. The film deposited at 2.0 W consisted of polycarbosilane-like main chains and side chains corresponding to the monomer structure. The film deposited at higher r.f. power consisted of a polycarbosilane-like main chain with more cross-links and less aromatic groups. The films synthesized at 2.0 W from phenylsilane had many submicrometre sized particles on the surface, but the films synthesized from phenylsilanes with methyl groups had few particles and smooth surfaces. The films deposited at higher r.f. power had many particles on their surfaces. The infrared spectra of methylphenylsilane polymer films were independent of the synthesis time, but film surface morphology changed from a smooth surface into a granular surface with an increase in the synthesis time. © 1998 Chapman & Hall     

Photochemical conversion of 2,5-diiodothiophene condensed on substrates to oligothiophene and polythiophene thin films and micro-patterns

A simple and efficient photochemical process for in-situ fabrication of oligothiophene and polythiophene thin films and patterns is demonstrated. The process involves vapor deposition of monomeric precursor molecules, 2,5-diiodothiophene on a substrate followed by photodissociation of the C-I bond to produce monomer radicals that further react in the condensed phase to produce oligothiophene and polythiophene. The thienyl molecular structure of the precursor is preserved during the photochemical process, providing good π conjugation of the produced polymer. Alkyl and cross-linking defects are negligible in the produced film. The direct conversion of the adsorbed monomer to the conjugated polymer allows easy fabrication of thin films and micro-patterns of polythiophene.     

Polymer films with surfaces unmodified and modified by non-thermal plasma as new substrates for cell adhesion

The surface properties of biomaterials, such as wettability, polar group distribution, and topography, play important roles in the behavior of cell adhesion and proliferation. Gaseous plasma discharges are among the most common means to modify the surface of a polymer without affecting its properties. Herein, we describe the surface modification of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) films using atmospheric pressure plasma processing through exposure to a dielectric barrier discharge (DBD). After treatment the film surface showed significant changes from hydrophobic to hydrophilic as the water contact angle decreasing from 95° to 37°. All plasma-treated films developed more hydrophilic surfaces compared to untreated films, although the reasons for the change in the surface properties of PS and PMMA differed, that is, the PS showed chemical changes and in the case of PMMA they were topographical. Excellent adhesion and cell proliferation were observed in all films. In vitro studies employing flow cytometry showed that the proliferation of L929 cells was higher in the film formed by a 1:1 mixture of PS/PMMA, which is consistent with the results of a previous study. These findings suggest better adhesion of L929 onto the 1:1 PS/PMMA modified film, indicating that this system is a new candidate biomaterial for tissue engineering.     

The influence of process parameters on the structure and morphology of pulsed plasma‐polymerized octafluorotoluene films

Abstract

This work describes amorphous fluorinated polymer films deposited by pulsed plasma polymerizations of octafluorotoluene (PPP‐OFT) monomers on ITO glass as the hole‐injection layer of organic electroluminescent (EL) devices, in order to study the influence of sample position and duty cycle on PPP‐OFT film characteristics, and also to find a good process to yield a higher retention degree of monomers and lower roughness of PPP‐OFT fluorocarbon films. Experimental results revealed that PPP‐OFT films deposited at positions far away from the RF coil and close to the monomer inlet showed less roughness than films deposited near the high RF‐flux regions. In addition, the retention of the monomers in the PPP‐OFT layer will be high if the deposition is conducted near the monomer inlet but some distance away from the RF electrode. Moreover, amorphous fluorinated polymer films can be deposited with higher fluorine to carbon (F/C) ratios and CF₂ contents at proper substrate positions by means of different sticking coefficients of free radicals dissociated by octafluorotoluene monomers.     

A free-standing poly(9-(6-(thiophene-3-yl)hexyl)-9H-carbazole) films: electrosyntheses from a novel carbazole monomer bearing thiophene moiety

The pursuit for the electrosyntheses of high quality polycarbazole (PCz) films is a great challenge for the application of polycabazoles. The incorporation of thiophene unit into carbazole monomer might result in a novel polymer having both the advantages of polythiophene and polycarbazole. As expected in this paper, a novel conducting polymer, free-standing poly(9-(6-(thiophene-3-yl)hexyl)-9H-carbazole) (PTh-H-Cz) films with electrical conductivity of 7.8 S/cm, were synthesized electrochemically by direct anodic oxidation of a novel carbazole monomer, 9-(6-(thiophene-3-yl)hexyl)-9H-carbazole (Th-H-Cz), in boron trifluoride diethyl etherate (BFEE) solution. Incorporation of thiophene unit into carbazole monomer as a pendant led to the electrodeposition of high quality PCz films with metallic shine. Fluorescence spectral study revealed that as-formed polymer film in solid state was a good blue light emitter with strong emission at about 410 nm. This high quality free-standing PTh-H-Cz film will facilitate their potential applications as blue-light-emitting materials in organic light-emitting dioxide.     

Morphological and physicochemical properties of spin-coated poly(3-octylthiophene)/polystyrene composite thin films

Poly(3-octylthiophene) (P3OT) was synthesized by direct oxidation of 3-octylthiophene with FeCl₃ as oxidant. Molecular weight of P3OT polymer was measured by size exclusion chromatography. Homogeneous poly(3-octylthiophene) (P3OT) and polystyrene (PS) composite films have been synthesized by spin-coating technique from toluene with different polymer concentrations. The doped films were obtained by immersion for 30 s in a 0.3 M ferric chloride (FeCl₃) solution in nitromethane. A classical percolation phenomenon was observed in the electrical properties of these blends, it was smaller than 5% of P3OT in the blend. Surface topographical changes were studied by atomic force microscopy (AFM). AFM images of the composite films revealed surface morphology variation as a function of different P3OT concentration in PS, phase segregation was observed, and PS is shown to segregate to the surface of the films. The higher PS solubility, in comparison with the P3OT solubility, in toluene resulted in PS/P3OT bilayers. The films exhibited pit and island like topography, the pit size changed with the polymer concentration. Optical absorption properties of the polymeric films were analyzed in pristine and doped state. In doped state, the bipolaronic bands at 0.5 and 1.6 eV are shown in a 4% conductive polymer in the PS/P3OT film. Finally thermogravimetric analysis was also made on the simple and composite polymers.