Film Inner Structure

The structure of nanometer-thick PEM films is inhomogeneous along the direction normal to the electrode due to the presence of the surface. Decher has developed a qualitative three-zone model to describe the PEM structure [3], The first zone, 

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The inner structure of polyelectrolyte multilayer films has been studied by neutron and X-ray reflectivity experiments by intercalating deuterated PSS into a nondeut-erated PSS/PAH assembly [94, 99]. An important lesson from these experiments is that polyelectrolytes in PEMs do not present well-defined layers but are rather interpenetrated or fussy systems. As a consequence, polyelectrolyte chains deposited in an adsorption step are intertwined with those deposited in the three or four previous adsorption cycles. When polyelectrolyte mobility is increased by immersion in NaCl 0.8 M, the interpenetration increases with time as the system evolves towards a fully mixed state in order to maximize its entropy ]100]. From the point of view of redox PEMs, polyelectrolyte interpenetration is advantageous in the sense that two layers of a redox polyelectrolyte can be in electrochemical contact even if they are separated by one or more layers of an electroinactive poly ion. For example, electrical connectivity between a layer of a redox polymer and the electrode is maintained even when separated by up to 2.5 insulating bUayers [67, 101-103]. 

Martin and coworkers tried to prepare carbon tubes from the carbonization of polyacrylonitrile (PAN) in the channels of anodic oxide film (10). A commercially available film with a pore diameter of 260 nm was immersed in an aqueous acrylonitrile solution. After adding initiators, the polymerization was carried out at acidic conditions under N2 flow at 40°C. The PAN formed during the reaction was deposited both on the pore walls and on both sides of the film. Then the Film was taken from the polymerization bath, followed by polishing both faces of the film to remove the PAN deposited on the faces. The resultant PAN/alumina composite film was heat-treated at 250°C in air, and then it was heat-treated at 600°C under Ar flow for 30 min to carbonize the PAN. Finally, this sample was repeatedly rinsed in I M NaOH solution for the dissolution of the alumina film. The SEM observation of this sample indicated the formation of carbon tubes with about 50 xm long, which corresponds to the thickness of the template film. The inner structure of these tubes was not clear because TEM observation was not done. The authors claim that it is possible to control the wall thickness of the tubes with varying the polymerization period. 

The fluorinated carbon-coated AAO film has an interesting adsorption characteristic that has not been reported so far. Figure 3.12 shows N2 adsorption/desorption isotherms at -196°C for the pristine carbon-coated AAO film and the films fluorinated at different temperatures [119]. The isotherm of the pristine film is characterized by the presence of a sharp rise and a hysteresis in a high relative pressure range. Such a steep increase can be ascribed to the capillary condensation of N2 gas into the nanochannels of the AAO films, that is, the inner space of the nanotubes embedded in the AAO films. The amount of N2 adsorbed by the condensation into the fluorinated channels is lower than that of the pristine one. Moreover, the amount drastically decreases with an increase in the severity of fluorination. Since TEM observation revealed that the inner structure of the fluorinated CNTs was not different from that of the pristine nanotubes, the reason why the N2 isotherm was so changed as in Figure 3.12 cannot be attributed to the alteration of the pore texture upon the... 

Results of recent theoretical and computer simulation studies of phase transitions in monolayer films of Lennard-Jones particles deposited on crystalline solids are discussed. DiflFerent approaches based on lattice gas and continuous space models of adsorbed films are considered. Some new results of Monte Carlo simulation study for melting and ordering in monolayer films formed on the (100) face of an fee crystal are presented and confronted with theoretical predictions. In particular, it is demonstrated that the inner structure of solid films and the mechanism of melting transition depend strongly on the effects due to the periodic variation of the gas - solid potential. 

Preliminary results of Monte Carlo simulation [183] have also demonstrated the usefulness of the bond - orientational order parameters in determining the inner structure of films adsorbed on the (100) face of an fee crystal. 

Water Uptake Measurements. The water absorption capability of films was determined by measurements of water rising by capillary action. The experimental device, also called Baumann apparatus is shown in Figure 1. The samples were cut in order to expose their inner structure to water rising. They were then coated on each of their faces (except the contact surface) with epoxide resin to prevent their swelling and put on fritted glass in contact with distilled water. The absorbed water volume versus time data is then recorded as water penetrates into the sample. 

To obtain information about the inner structures, cross-sections of cut films were also examined by SEM (Figure 3). The micrographs, at x 5000 magnification, show some differences between both films, the thermomoulded sample being much rougher than the cast one. However, both films presented pores of about 200 to 500 nm diameter. 

FIGURE 6.3.2 An image of electronic artificial skin attached on the robot surface. A plastic film with organic transistors, a pressure-sensitive rubber sheet, and a plastic film with top electrodes are laminated together to form a large-area pressure sensor. Some parts of films are removed intentionally to show the inner structures. 

Ultrathin films of poly(isobutyl methacrylate) (PiBMA) have been investigated to demonstrate the ability of single polymer imaging, because they form a stable monolayer on the water surface with a thickness of only 1 nm, and sequential deposition of the monolayer provides very flat thin films with a tailor made inner structure [61]. Scheme 2 depicts the chemical structures of sample polymers. Besides the non-labeled PiBMA homopolymer, a labeled PiBMA (PiBMA-Pe) was synthesized by means of copolymerization of isobutyl methacrylate and 3-perylenylmethyl methacrylate. The copolymer... 

The sample was prepared by radical copolymerization of MMA monomer in toluene solutions containing a small amount of 3-perylenyImethyl methacrylate as a fluorescent monomer and ethylene glycol dimethacrylate as a cross-linker. The sample for SNOM measurements was prepared from the solid gel thus obtained, which was sliced using a microtome, yielding a very thin film with a thickness of ca. 100 nm, and then the inner structure was observed by SNOM. 

After passage through the specimen the electron beam broadens and projects a magnified picture of the inner structure of the object. The image can be observed on a fluorescent screen or, alternatively, the transmitted electrons can be used to expose a photographic film, which after development gives a picture of the structure. 

The performance of this microscope is shown in Fig. 18. The sample consists of a pho-topatterned LB film with dimensions indicated in the figure. The image on the left hand side sketches the inner structure of the sample. 

CFM 56 Here both aluminium and carbon reinforced composite sandwich panel constructions are used. An aluminium bondment forms the inner structure of the acoustic panel. Perforated, Redux 119 primed skins are bonded to aluminium honeycomb, Redux 319 film adhesive having first been reticulated onto the core. The outer structure is a conventional bondment of a carbon reinforced composite skin bonded to the core. 

Figure 13.3 Inner structures of granulates from corn starch (a) (Jenkins and Donald, 1995) and morphology of cassava starch film plasticized with glycerol and water (b) (Johar and Ahmad, 2012).

Fig. 9 (a) Molecular structures of novel ESIPT dyes, 2,5,-bis[5-(4-t-butylphenyl)-[l,3,4]oxadia-zol-2-yl]-phenol (SOX), and 2,5-bis[5-(4-t-butylphenyl)-[l,3,4]oxadiazol-2-yl]-benzene-l,4,-diol (DOX). (b) Emission colors in the Commission Internationale de L Eclariage (CEE) chromaticity diagram. The inner oval and the filled circle at coordinate (x,y) of (0.33, 0.33) indicate the white region and the ideal color, respectively. Note that PS and PVK denote polystyrene and poly (N-vinylcarbazole) film (reprint from ref. [91], Copyright 2005 Wiley-VCH)... 

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