Properties Of Polymer Films Research Articles

Synteza kopolimerow poli(uretanowo-metakrylowych) z zastosowaniem makroinicjatora tetrafenyloetanouretanowego metoda polimeryzacji kontrolowanej ARGET ATRP

Poly(methyl methacrylate)-b-polyurethane-b-poly(methyl methacrylate) tri-block copolymers were synthesized for the first time using ARGET ATRP method. A specially prepared for this purpose tetraphenylethane-urethane macroinitiator (TPE-PUR-TPE) was used as a transitional product reacting with methyl methacrylate (MMA) in the presence of CuBr2 or CuCl2 catalyst and N,N,N',N”,N”-pentamethyldiethylenetriamine (PMDETA) or 2,2'-bipyridine (Bpy) as a complexing agent. It was found that both the molecular weight of the resulting copolymer versus MMA conversion and the value of ln([M]0/[M]) as a function of polymerization time increase linearly. High coefficients of linear correlation for the studied relationships indicate that the formation of tri-block copolymers takes place according to the mechanism of atom transfer radical polymerization. The results of FT-IR, 1H and 13C NMR spectral analyses as well as DSC and TGA thermal studies confirm the expected chemical structure of the synthesized macroinitiator and poly(urethane-methacrylate) copolymers produced with its involvement. Additionaly, the studies of surface properties (roughness, contact angle and SFE) of polymer films prepared from these copolymers indicate, based on the observed increase of hydrophobicity, the presence of block segments derived from PMMA.

The influence of different electrolytes on the electrical and optical properties of polymer films electrochemically synthesized from 3-alkylthiophenes

In this study, we observed significant differences in the electrical and optical properties of polymer films electrochemically synthesized from two 3-alkylthiophene monomers on platinum wires in 0.100 mol L−1 LiClO4/acetonitrile (ACN) or Et4NBF4/ACN, when compared to the following homopolymer films: poly(3-methylthiophene) (P3MT), poly(3-hexylthiophene) (P3HT) and poly(3-octylthiophene) (P3OT), prepared under the same conditions. Electrical impedance spectroscopy was used to assess the resistive and capacitive properties of the polymer films [P3MT and P3HT—CP3(MT-HT); P3MT and P3OT—CP3(MT-OT); P3HT and P3OT—CP3(HT-OT)] at overpotentials determined beforehand by Cyclic Voltammetry. The films synthesized in LiClO4/ACN with the lowest charge transfer resistance values were CP3(MT-HT) and CP3(MT-OT), and synthesized in Et4NBF4/ACN, CP3(HT-OT). In terms of their optical properties, the films synthesized in LiClO4/ACN exhibited hypsochromic shift of E g values and a drop in electron affinity values by comparison with homopolymer films and those synthesized in Et4NBF4/ACN. Based on Photoluminescence (PL) Spectroscopy it was possible to identify the contributions of the quinone and aromatic segments characteristic of homopolymers in the films synthesized in Et4NBF4/ACN. For the films synthesized in LiClO4/ACN, it was not possible to perform the same comparison because there was a discrepancy between the bands observed in the PL images of these materials and those of the homopolymers, suggesting the formation of not only blend structures but also copolymer films. Using Raman Spectroscopy it was possible to identify aromatic, radical cation and dication segments and verify the higher stabilization of radical cation and dication segments in resistive films. It was also possible to observe changes in the morphological structures of the films by comparison with the homopolymers, in addition to alterations due to changes in electrolyte during synthesis using scanning electron microscopy.

Simple strategy to tune the charge transport properties of conjugated polymer/carbon nanotube composites using an electric field assisted deposition technique

Work concerning the incorporation of carbon nanotubes (CNTs) in organic semiconducting polymers have now been reported by many research groups, and the electrical properties of polymer/CNT nanocomposites have been extensively studied. In this work, we present a simple procedure to tune the charge transport properties of planar organic polymer films based on poly(3-hexylthiophene) (P3HT). The polymer/CNT composites are simultaneously processed and oriented from solution using an electric field assisted orientation technique. We first study the behavior of CNTs alone during the alignment procedure and emphasize the main experimental parameters that drive their final orientation on the substrate. By quantitatively analyzing the CNT angular distribution on the substrate, we show that the dielectric constant of the solvent used to disperse and deposit the CNTs is crucial to ensure an efficient orientation, and that a dielectrophoresis-like orientation procedure occurs. The transposition of this approach to planar P3HT/CNT composites is made by investigating the electric properties in ambient conditions of aligned and non-aligned devices. Current–voltage characteristics show a drastic increase of the composite conductivity upon addition and alignment of CNTs. Field-effect transistor charge mobilities are improved by an order of magnitude upon addition of CNT (1 wt%) in P3HT, and another decade is gained using the optimized alignment parameters, without any additional annealing. These results demonstrate the strong potentialities of our approach in the field of printed electronics and organic optoelectronics. © 2013 Society of Chemical Industry

Electrosynthesis and Characterization of the Donor-Acceptor Type Multicolored Electrochromic Materials

Two novel monomer were synthesized via Stille cross coupling reaction. Electropolymerization of the monomers gave birth to the donor-acceptor type polymers: poly{10,13-bis(2,3-dihydrothieno(3,4-b)(1,4)dioxin-5-yl) diben- zo(a,c)phenazine} (P1) and poly{10,13-bis(4-ethylthiophen-2-yl)dibenzo(a,c)phenazine} (P2). Cyclic voltammetry and UV-vis spectroscopy were used to study the electrochemical and optical properties of the polymer films. The surface mor- phologies of the polymer films were investigated by scanning electron microscopy (SEM). The slight structural modification of the two polymer films results in the variation of the optical and electronic properties. As shown in the studies, P1 film was green in the neutral state, and with the increment of the applied potentials, four different colors were observed (light green, greyish-green, grey and cadet blue). The P1 film had prominent high optical contrast (T%) of 74.8%, excellent response time of 0.6 s and good coloration efficiency (CE) of 285.8 cm 2 /C at 1600 nm. Electrochromic switching response for polymer film P1 at 470 nm, 790 nm was also monitored. The slight loss in percent transmittance contrast value at the three given wave- lengths indicated the stable ability of the polymer film of P1. The colors of polymer film P2 in the neutral and oxidized state were greyish-blue and cadet green, respectively. The optical contrast (T%) of P2 film was found to be 64.5%, the response time was 2.4 s and the coloration efficiency (CE) was 316.7 cm 2 /C at the wavelength of 1340 nm. P2 film showed high sta- bility at the wavelength of 1340 nm, but at 754 nm the stability was not satisfactory. Moreover, both of the two polymers exhibited low optical bandgap (Eg) (the Eg of P1 was 1.26 eV and the Eg of P2 was 1.54 eV). Both polymer films revealed obvious donor-acceptor behaviors, and they were not only n-dopable but also p-dopable. Keywords dibenzo(a,c)phenazine; conducting polymers; donor-acceptor behavior; electrochemical polymerization; elec- trochromism

Synthesis and Properties of a Novel Spirooxazine Dye

A novel bifunctional photochromic compound 2 based on spirooxazine and cinnamoyl moiety was synthesized by esterification reaction. Its structure was characterized by 1 H NMR, 13 C NMR, IR and X-ray single crystal diffraction. The compound was proved by UV testing to have excellent photochromic properties both in organic solvents and polymer films when irridiated with high pressure Hg lamp. The acidichromism phenomenon of compound 2 was studied too. No significant fluorescence emission of compound 2 was observed in EtOH solution before and after irradiation. Under the acidic condition or irradiation with 150 W Xe lamp, The ethanol solution of compound 2 exhibits a good fluorescence respectively. The ethanol solution of compound 2 exhibits obvious fluorescence emission. After irradiating the acidic solution, new fluorescence emis- sion can be observed. The emission change modulated by acid or light offers compound 2 to be potential as a new fluorescent molecular switch. Keywords spirooxazine; photochromism; cinnamate; acidichromism; fluorescence

J0420104 基板表面と裏面での高分子フィルム吸着時における音響共鳴現象の観察([J042-01]超音波計測・解析法の新展開(1),機械材料・材料加工部門)

Acoustic properties, e.g., acoustic impedance, sound velocity, etc., are used for characterizing polymer materials. It has been reported that the acoustic properties of thin polymer films can be characterized using acoustic resonance phenomenon occurring among the water, polymer film and reflection plate. We observe acoustic resonance phenomenon at both surfaces of the reflection plate contacted with a polymer film, and measure the sound velocity of the film from the resonant frequency.

Interfacial polarization and layer thickness effect on electrical insulation in multilayered polysulfone/poly(vinylidene fluoride) films

In this study, we report layer thickness effect on the electrical insulation property of polysulfone (PSF)/poly(vinylidene fluoride) (PVDF) multilayer films having a fixed composition of PSF/PVDF = 30/70 (vol./vol.). Breakdown strength, dielectric lifetime, and electrical conductivity were studied for 32- and 256-layer films having various total film thicknesses. Among these films, those having thinner PVDF and PSF layers exhibited lower breakdown strength, shorter lifetime, and higher electrical conductivity than those having thicker layers. These experimental results were explained by Maxwell–Wagner–Sillars interfacial polarization due to contrasts in dielectric constant and electronic conductivity for PVDF and PSF, respectively. When both PVDF and PSF layers were thick (ca. > 100–200 nm), more space charges were available in PVDF and no electronic conduction was allowed for PSF. These accumulated interfacial charges could serve as effective traps for injected electrons from metal electrodes under high electric fields. As a result, reduced electrical conductivity and enhanced breakdown strength/dielectric lifetime properties were obtained. When both layers were thin (ca. < 100 nm), fewer space charges were available in PVDF and significant electronic conduction through PSF resulted in low interfacial polarization. Consequently, higher electrical conductivity, lower breakdown strength, and shorter lifetime were observed. These results provide us insights into potential physics to enhance electrical insulation property of polymer films using a multilayered structure having large dielectric constant contrast.

Determination of Thermal Transition Depth Profiles in Polymer Semiconductor Films with Ellipsometry

Geometric confinement and interface effects can significantly alter the thermodynamic properties of thin polymer films. Phase transition temperatures have been shown to strongly depend on film thickness below a critical thickness threshold. It has been suggested that this behavior is due to an interface-induced continuous variation in phase transition temperatures throughout the depth of the films. Here we employ variable-temperature spectroscopic ellipsometry to demonstrate the existence of these depth profiles. We examine four different polymer semiconductors that are of interest for organic light-emitting diodes, solar cells, and field-effect transistors. In contrast to insulating polymers, these light-absorbing materials provide detailed information about structural changes as a function of depth due to wavelength-dependent attenuation. This concept enables us to investigate a broad range of thermodynamic processes including the glass transition, crystallization as well as crystalline and liquid-cryst...

Influence of residual solvent on physical and chemical properties of amorphous glassy polymer films

One of the most important areas of current research is the study of the influence of the prehistory of samples of amorphous glassypolymersontheirphysicalandchemicalproperties.ThestudyofstructuralchangesbyhightemperatureIRspectroscopy compared with of quantum chemical calculations allows for an understanding of the mechanism and nature of such processes. The changes in the structure of the polymer chain depending on the type of solvent used in the formation of the films are demonstrated using the examples of several different classes of polymers. In turn, the impact of such changes in the structure on the physical and chemical properties of the polymer films is demonstrated. c � 2013 Society of Chemical Industry

Thermal and Mechanical Properties of Glycerol-Based Polymer Films Infused with Plant Cell Wall Polysaccharides

Poly(glutaric acid-co-glycerol) films were produced by first synthesizing polymer gels from the uncatalyzed polyesterification of glutaric acid and glycerol in toluene. Residual amounts of starting materials in the gel matrices were determined by gas chromatography (GC) to contain 16.4% glutaric acid and 0.2% glycerol or 0.6% glutaric acid and 15% glycerol, respectively for the 2:1 and 1:2 (glutaric acid:glycerol) molar ratio formulations. The 2:1 (glutaric acid:glycerol) polymer gel formulation was cured with and without the incorporation of lignocellulosic biomass (sugarcane bagasse) or purified plant cell wall polysaccharides (corn fiber gum, pectin, or microcrystalline cellulose) at 135 C for 12 h to form polymer composite films. The 1:2 (glutaric acid:glycerol) gel formulation was cured at 135 C for 24 h. ATR-IR results suggest that the films were completely cured. Heat capacity ( Cp) and glass transition temperature (Tg for all specimens averaged 0.41 (±0.1) J/g∗ C and −14.8 (±2.0) C, respectively. The thermal curves of the polymers showed total degradation for all polymer films at approximately 400 C. The addition of microcrystalline cellulose into the polymer matrix showed a 3-fold increase in tensile strength and Young’s modulus and a two-fold increase in fracture energy when compared to the cellulose-free polymer film made only from a 2:1 molar ratio of glutaric acid to glycerol.

Fabrication of organic interfacial layers by molecular layer deposition: Present status and future opportunities

To keep pace with the miniaturization of next generation devices in applications such as electronics, biotechnology, and energy, their constituent polymer thin films must meet challenging requirements such as providing simultaneously ultrathin and conformal coatings. Traditional polymer deposition methods may not be suitable, and as a result, new fabrication methods are needed. Molecular layer deposition (MLD), as an analog to atomic layer deposition, provides precise control over many polymer film properties, such as thickness, composition, morphology, and conformality. Hence, MLD can be a powerful and novel method for fabrication of polymer films. This review article introduces the variety of polymer films that have been developed using MLD together with important film growth characteristics and properties. Examples of MLD polymer applications are provided as well. Finally, challenges and outlooks of the MLD technique are discussed.

Increase the Reliability and Applicability of Quartz Crystal Resonator Coupled with Other Instruments

The principle and applications of quartz-crystal resonator systems and the methods to increase their reliability and applicability coupled with other instruments were reported. The principle of quartz-crystal resonator system was documented with based on the three basic concepts for mass, viscosity, and viscoelastic changes. In the preliminary discussion, the realization of a resonant frequency-resonant resistance diagram was described in detail. As the examples of quartz-crystal resonator applications with introducing the resonant resistance concept and the resonant frequency, the fabrication of a carbon-coated quartz crystal sensor and monitoring changes in the viscoelastic properties of thin polymer films were carefully discussed. Examples for increasing their reliability and applicability of quartz crystal resonator systems combined with UV-visible spectroscopy, Atomic Force Microscope (AFM), Surface Plasmon Resonance (SPR), or Charge Coupled Device (CdCD) camera were described.

Study of structural and free volume properties of swift heavy ion irradiated Polyallyl diglycol carbonate polymer films

Structural and free volume properties of polyallyl diglycol carbonate (PADC) commercially known as CR-39 polymer films of thickness 250 μm were irradiated with 50 MeV Li3+ ions at the fluences ranging from 1 × 1011 to 1 × 1014 ions/cm2. The structural studies were investigated by X-ray diffraction measurement. The crystallite size as well as percentage crystallinity was calculated from the X-ray diffraction data. The change in the crystallite size, peak broadening and variation in the intensity of X-ray peak shows significant increase in amorphous phases of the polymer samples at higher fluences. Free volume properties were studied by Positron Annihilation Lifetime Spectroscopy (PALS). Hole radius (R), free volume (Vf) and fractional free volume (Fv) were calculated by using the Tao–Eldrup Model. There is a gradual decrease in the hole radius and free volume up to the fluence of 1 × 1012 ions/cm2. It could be attributed to the cross linking of polymer chains whereas subsequent irradiation resulted in an additional defect generation that aided to the free volume growth by their condensation on to the existing free volume defects. The free volume increases at higher fluences whereas degree of crystallinity shows opposite behavior at higher fluences.

Functionalized polymer film surfaces via surface-initiated atom transfer radical polymerization

The ability to manipulate and control the surface properties of polymer films, without altering the substrate properties, is crucial to their wide-spread applications. In this work, a simple one-step method for the direct immobilization of benzyl chloride groups (as the effective atom transfer radical polymerization (ATRP) initiators) on the polymer films was developed via benzophenone-induced coupling of 4-vinylbenzyl chloride (VBC). Polyethylene (PE) and nylon films were selected as examples of polymer films to illustrate the functionalization of film surfaces via surface-initiated ATRP. Functional polymer brushes of (2-dimethylamino)ethyl methacrylate, sodium 4-styrenesulfonate, 2-hydroxyethyl methacrylate and glycidyl methacrylate, as well as their block copolymer brushes, have been prepared via surface-initiated ATRP from the VBC-coupled PE or nylon film surfaces. With the development of a simple approach to the covalent immobilization of ATRP initiators on polymer film surfaces and the inherent versatility of surface-initiated ATRP, the surface functionality of polymer films can be precisely tailored.

Simple technique for the simultaneous determination of solvent diffusion coefficient in polymer by Quantum Resistive Sensors and FT‐IR spectroscopy

A simple, quick and novel method for the determination of diffusion properties through polymer films, based on Quantum Resistive Sensors made of Conductive Polymer nanoComposites is presented. The integral time lag method is employed for the calculation of diffusion coefficient, and the results are compared simultaneously with that of Fourier transform infrared spectroscopy and sorption method. Two model polymers, a semi‐crystalline poly(lactic acid) and an amorphous poly(isobutylene‐co‐isoprene), are used to validate the study. A good correlation is established between the diffusion coefficient values derived from all techniques demonstrating the interest of such reliable, simple and cheap nanosensors for the quick determination (several minutes) of diffusion properties in polymer films. Our first results suggest that this technique is meaningful for the determination of barrier properties in nanocomposite membranes filled with platelets of graphene or clay. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Parameter passing between molecular dynamics and continuum models for droplets on solid substrates: The static case

We study equilibrium properties of polymer films and droplets on a solid substrate employing particle-based simulation techniques (molecular dynamics) and a continuum description. Parameter-passing techniques are explored that facilitate a detailed comparison of the two models. In particular, the liquid-vapor, solid-liquid, and solid-vapor interface tensions, and the Derjaguin or disjoining pressure are determined by molecular dynamics simulations. This information is then introduced into continuum descriptions accounting for (i) the full curvature and (ii) a long-wave approximation of the curvature (thin film model). A comparison of the dependence of the contact angle on droplet size indicates that the theories agree well if the contact angles are defined in a compatible manner.

A comparison of effect of PEG and EC plasticizers on relaxation dynamics of PEO–PMMA–AgNO3 polymer blends

In the present study, Ag+-ion conducting polyethylene oxide–polymethyl methacrylate based polymer blend electrolyte systems plasticized using different plasticizers, i.e., ethylene carbonate and polyethylene glycol, are reported. The polymer films were synthesized using the solution cast technique and characterized by differential scanning calorimetry technique. Electrical properties of polymer films were investigated by impedance spectroscopy in the frequency range of 2 MHz–10 Hz at temperature range from 303 to 373 K. Discussion of electrical properties of polymer films in the terms of conductivity and relaxation times is made.

Is ballistic transportation or quantum confinement responsible for changes in the electrical properties of thin polymer films?

Resistivities of thin polymer films increase abruptly with decreasing thickness, although the corresponding decline in resistance plateaus below a certain thickness. One can jump to the incorrect conclusion that quantum confinement and surface scattering are responsible for this behaviour, and we highlight the pitfalls of committing such an error.

The link between mechanisms of deposition and the physico-chemical properties of plasma polymer films

Film thickness and functional group retention are routinely measured parameters for plasma polymers. It is known that other parameters such as density, solubility and mechanical properties can affect the performance of the plasma polymer film, however such parameters are not often measured; nor is there any understanding of the link between the mechanisms of film growth and these properties. In this investigation we produced thin films from three classes of commonly used plasma polymers (hydrocarbons, glymes and carboxylic acids). By choosing the monomer structure and applied RF power, the dominant mechanism of film growth was varied between ionic deposition and neutral grafting. The density, solubility and modulus of the resulting films were then measured by atomic force microscopy. Films grown from saturated monomers had higher moduli, were less soluble, and surprisingly had lower density compared to their unsaturated analogues. The results demonstrate that cognizance of the mechanism of film growth allows the physical properties of the film to be tailored for specific applications.

Influnce of heat treatment on the structure and optical properties of glow discharge polymer films

The glow discharge polymer (GDP) films each with a thickness of about 5 m are deposited by low-pressure plasma polymer apparatus. The GDP films are heat-treated at different tempertures of 280, 300, 320 and 340 ℃ in Ar atmosphere. The influence of heat treatment on the structure of GDP film is characterized by FT-IR. The optical transparency and optical band of GDP film are investigated by UV-VIS spectrum. The results show that with temperature increasing, the relative content of CH3 decreases, while the relative content values of CH2 and CH increase. The H content in GDP film decreases. The optical band gap decreases, and the transmittance in a range of more than 600nm decreases too.