Poly layer thickness variations

Figure 14 shows the variation of the steady shear relative viscosity at the high shear limit with the effective volume fraction as defined by equation 46 for poly(methyl methacrylate) (PMMA) suspensions of different sizes in decalin sterically stabilized by means of grafted poly (12-hydroxy stearic acid) chains with a degree of polymerization of 5. The stabilizing polymer layer thickness is 9 1 nm, in particular, A = 9 nm... 

FIGURE 1.87. Variation of low-frequency capacitance C/, with layer thickness for a Cl -doped poly(pyrrole) film in 0.1 M NaCl, applied potential, 400 mV. 

Figure 44 MISFET structure with poly n-silicon source and drain contacts with polyacetylene layer thickness of 20 nm. Shown here is the variation of Ids with Vgs for Vds =+10 V.

The permeable membrane (barrier layer) plays a crucial role for the ALILE process. Usually, the barrier layer is formed by exposure of the Al-coated glass substrate to air. The thickness of this barrier layer (A1 oxide), which is on a nanometer scale, can be influenced by the variation of the exposure time. With increasing exposure time, the thickness of the barrier layer increases. The thicker the barrier layer, the lower is the nucleation density and the longer is the process time necessary to form a continuous poly-Si film [19]. By X-ray photoelectron spectroscopy (XPS) measurements it was shown that the barrier layer stays in place during the whole ALILE process. 

Figure 16 shows the steady shear relative viscosity variation with the effective Peclet number, Peeg, based on the effective particle diameter at each temperature level, and the temperature for a PMMA suspension. The particles of 0.8 pm are sterically stabilized by a thick layer of terminally anchored poly(dimethylsiloxane) and suspended in n-hexadecane at the volume fraction of 0 = 0.282. The data points are... 

Figure 3. Variation with dioxane concentration of the parameters of the lamellar structure of the copolymer SG.5 with a polystyrene block of 25,000 and a poly(benzyl glutamate) content of 47%. ( ) Total thickness d of a sheet (A) thickness d 4 of the polystyrene layer (O) thickness d/, of the polypeptide layer.

Fig. 5.4(b) shows typical reflectivity data from a thin polymer film on an aqueous surface (Wang et al., 2013). A thick poly(D,L-lactic acid) (PDLLA) film that is formed at higher pressures (21 mN/m) causes multiple oscillations. These oscillations are absent in the diffuse polymer layer at lower pressures (15 mN/m). The spacing between ripples corresponds to the thickness of the layer. The rate of fall of the overall profile is determined by the surface roughness, and the height of the ripples depends on the density contrast between the substrate and the deposited film. The total XRR curve can also be used to model the density variation across the depth. This is shown by the electron density distributions derived from the data (Fig. 5.4(c)). 

Stassen et al. [1026] described an interesting application for a supported CP membrane constructed by electrodepositing a 1 to 6 ixm thick film of poly(3-hexyl-thiophene) onto a thin (20 nm) Au layer deposited in turn on a Millipore Durapore membrane (average pore size 0.1 /im), i.e. the final configuration was CP/Au/-Durapore. They then mounted this membrane in a test cell and measured the permeability of the neurotransmitter dopamine (Dopa) through it as a function of potential applied to the membrane. They however found a poor variation of the permeation rate, only of the order of 40%. Response time for observable permeation was also poor, being of the order of hours. 

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