Thickness measurements polymer

Iron, thickness measurement, 150-152 trace analysis by x-ray emission spectrography, 163, 225-232 Iron-55, as x-ray source for sulfur determination, 130, 133-135 Iron oxides, analysis, 182, 184 Irradiance, definition, 6 Irradiation, equipment for, 177 of polymers, 177... 

PVA and TaM -for the 88%-hydrolyzed PVA. The same dependence was found for the adsorbed layer thickness measured by viscosity and photon correlation spectroscopy. Extension of the adsorption isotherms to higher concentrations gave a second rise in surface concentration, which was attributed to multilayer adsorption and incipient phase separation at the interface. The latex particle size had no effect on the adsorption density however, the thickness of the adsorbed layer increased with increasing particle size, which was attributed to changes in the configuration of the adsorbed polymer molecules. The electrolyte stability of the bare and PVA-covered particles showed that the bare particles coagulated in the primary minimum and the PVA-covered particles flocculated in the secondary minimum and the larger particles were less stable than the smaller particles. 

The experimental thickness measurements may also be compared with theoretical results based on profiles generated by the S.F., Scheutjens Fleer, theory (11). For this calculation we use a value for xs °f 1 (net adsorption free energy), for x of 0.45 (experimental value of the Flory-Huggins parameter) and a polymer solution concentration of 200 ppm. Although the value for xs seems rather arbitrary it has been shown (10) that 6jj is insensitive to this parameter. 

Segment density profiles and hydrodynamic thickness measurements have been made for polyethylene oxides adsorbed on polystyrene latex. Comparison with theoretical models shows that the hydro-dynamic thickness is determined by polymer segments (tails) at the extremity of the distribution. It is also concluded that the sensitivity of the s.a.n.s. experiment precludes the measurement of segments in this region and that the experimental segment density profiles are essentially dominated by loops and trains. 

Watanabe and Ohnishi [39] have proposed another model for the polymer consumption rate (in place of Eq. 2) and have also integrated their model to obtain the time dependence of the oxide thickness. Time dependent oxide thickness measurement in the transient regime is the clearest way to test the kinetic assumptions in these models however, neither model has been subjected to experimental verification in the transient regime. Equation 9 may be used to obtain time dependent oxide thickness estimates from the time dependence of the total thickness loss, but such results have not been published. Hartney et al. [42] have recently used variable angle XPS spectroscopy to determine the time dependence of the oxide thickness for two organosilicon polymers and several etching conditions. They did not present kinetic model fits to their results, nor did they compare their results to time dependent thickness estimates from the material balance (Eq. 9). More research on the transient regime is needed to determine the validity of Eq. 10 or the comparable result for the kinetic model presented by Watanabe and Ohnishi [39]. 

Instead of the simultaneously extmded polymer film, a pre-extmded or laminated film can be laminated on the substrate (e.g., paper or paper board). In this case, the extruder can be used to extrude the polymer providing adhesion (e.g., Ecoflex ) in a thin layer between the polymer coating film or laminate and the substrate. Another option is to apply a dispersion or heat in the laminator (Fig. 10, 4) to obtain adhesion. After thickness measurement and second subsequent corona treatment, substrate and polymer coating are wound on a winder (Fig. 10, 6) in order to obtain rolls for transport to subsequent processes (e.g., printing, cutting, cup forming, box making). 

Quite similar results have been reported by van Vliet [226]. He found that the equilibrium thickness of foam films from aqueous solutions of polyvinyl alcohol at low pressure is much larger than twice the adsorption layer thickness measured by ellipsometry. The core thickness is again several times the radius of gyration of the polymer molecules in... 

CdSe nanocrystal solutions in toluene were obtained from Evident Technologies (Troy, NY). Concentrations of 2.8 and 5.6-nm CdSe nanocrystals were 2.5mg/mL. Sensor films were spin-cast from 5% vol. solutions of nanocrystals in polymer/toluene. Polymers tested as matrices for the CdSe nanocrystals are fisted in Table 5.1. Film thickness measured using an interference microscope was found to be under 1 om. 

A hybrid structure which was composed of 50 nm-thick SiNx and 3 jtan-thick acrylic polymer was chosen as passivation layer as shown in the Fig. 10. TFTs were stressed by outward cylindrical bending at the radius of curvature R = 5 mm. Before bending the TFTs, electrical p>erformances measured. The TFTs were stressed for 24 hours. The transfer characteristics of... 

TFTs in the bended condition (R = 5 mm) were measured at arbitrary intervals as shown in Fig. 11 (left) and 12. A zero hour duration time meant that TFTs were measured as flattened before bending them. The mobility change ( ife/nfeo) of 0.92, the subthreshold slope change (SS/SSo) of 1.04, and the threshold voltage shift (AVth) of 1.03 are almost same as those of TFT employing the single acryl passivation. As the 50 nm-thick SiNx and 3 )can-thick acrylic polymer were employed as the passivation, the position of the neutral plane may shift from mid-surface toward the TFT-films. These results are similar to that of a single acrylic polymer passivation. 

The data reproducibility was excellent as long as a single batch of control resin was used for the studies so that variables such as monomer purity and polymer molecular weight were controlled. In addition films were cast in a clean room to minimize dust incorporation which can result in large errors in film thickness measurements. Figure 3 shows the typical example and the worst case for dielectric constant data variability on these films. 

Much less information is available on the methods for the determination of the interphasial thickness in polymer blends, Al, than that of Vj - For binary systems, assuming that these two parameters are interrelated, one may estimate Al from Vj, the latter determined using one of the above-described methods. To determine the experimental value of Al in any system, diverse methods have been used, viz. electronic microscopy. X-ray scattering, eUipsometry [Inoue, 1991 Fayt, 1986], light scattering, etc. Results of these measurements are presented in the next section (see Table 4.6). 

The thickness of the polymer coatings was determined as follows. Polymer films were spin cast (15) from a MDI/ED/PTMO polyurethaneurea of known composition. The film thickness, measured by a micrometer, was found to correlate linearly with the height of the 1600 cm peak (v(C C) benzene ring), thus allowing determination of a Beer s law extinction coeffecient for the mass fraction of benzene rings in these polymers. Transmission spectra of the dip coated IRE s were obtained, and the polymer thickness determined assuming that the Beer s law extinction coefficient was unchanged on these thin films. 

Where polymers transfer to counterface surfaces in extremely thin film forms, of the order of monolayers the surface profilometer becomes ineffective and other tools must be used. A device which can measure the thickness of such films is the ellipsometer. It can detect film thicknesses of polymers on the order of angstroms. 

Just as the ellipsometer can be used to measure polymer film thickness so can XPS. For example, with PTFE by the use of the ratio of intensities of the F(ls) and the C(ls) peaks and the attenuation of the nickel peak intensities it is possible to measure polymer film thickness and accordingly polymer wear (2) ... 

Polymer Structure. In addition to visualization, profiling, thickness measurements and chemistry of polymer wear it is frequently desirable to know whether the polymer is in the amorphous or crystalline state because other properties relate to state. Raman spectroscopy is very useful in studying very low frequency modes associated with vibrations of polymer chain backbones and the lattice modes of polymer crystals. It complements infrared spectroscopy. 

The thickness of polymer transfer films to counterface surfaces can be measured with sensitivities into the angstrom range with the ellipsometer. The device can be arranged for in situ thin film measurements. 

R.F.M. Lobo, M.A. Pereira da Silva, M. Raposo, RAi. Faria, O.N. Oliveira Jr, In si/u thickness measurements of ultra-thin multilayer polymer films by atomic force microscopy. Nanotechnology, 10, 389-393 (1999). 

Layer thickness and polymer concentration is obtained directly by ellipsometry, that is, the change in elliptically polarized light after reflection from a surface covered by an adsorbed layer. The number of adsorbed segments is accessible via infrared spectroscopic studies as well as via calorimetric adsorption enthalpy measurements. 

Fig. 9-22. Calculated and observed phase diagrams for PS f4 + PS fl28 (the weight fraction of the latter is 0.05) + CH on the T — ( > plane. Thick solid line, calculated cloud-point curve. Dot-dashed line, calculated shadow curve. Dashed lines, calculated two-phase conjugate coexistence curves for the indicated polymer volume fractions. Thin solid line, three-phase coexistence curve. Unfilled circle, calculated critical point. Filled circles, measured cloud points. Filled triangles, measured polymer volume fractions in three separated phases. 

Uchikawa et al. [24] obtained very interesting results measuring the thickness of polymer layer adsorbed on cement grains by Auger electron spectroscopy. Thick-... 

Gibson, A.G. at al. (1978). Dynamic mechanical behaviour and longitudinal crystal thickness measurements on ultra-high modulus linear polyethylene a quantitative model for the elastic modulus. Polymer, Vol. 19 (1978), pp. 683-693 Hong, K. et al. (2004). A model treating tensile deformation of semi-crystalline polymers Quasi-static stress-strain relationship and viscous stress determined for a sample of... 

The operating temperature range is typically 100 -1000 K using samples of area 30-50 mm and thickness 0.01-0.3 mm. The temperature resolution is 0.0025 K for T< 770 K and 0.025 K for r> 770 K. The sample holder is purged with a dry inert gas. Alumel-chromel or chromel-constantan thermocouples of 0.002 mm diameter are placed in a paper frame and soldered to metal samples to measure. Polymers are dissolved in an organic solvent and the solution is spread on a thin metal... 

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