Membranes, imaging

Fig. 5.9. AFM image of a Lavsan filtration membrane. Image size 5 )xm x 5 )xm, depth scale 500 nm from black to white.

Moreaux, L., Sandre, O., Blanchard-Desce, M., and Mertz, J. 2000a. Membrane imaging by simultaneous second-harmonic generation and two-photon microscopy. Opt. Lett. 25 320-22. 

Stack together the film and nitrocellulose membrane images, aligning the upper left comers and the two corresponding borders and placing the cut lower right comer in the same orientation for both. 

Membrane imaging techniques based on the measurement of the local solution conductivity using scanning ion conductance microscopes have also... 

Dietz et al. [9] studied AFM images of three capillary pore membranes and eight UF membranes. The membranes imaged by Dietz et al. are Hsted in Table 5.2. 

Fig. 1 (a) EE-based nanoporous pyramidal plane applied in pyramidal-textured Si solar cells (Kim et al. 2009). (b) SEM cross-sectional view of a gold-coated thin PS film prepared from HNO3/HF vapor etching (Ben Jaballah et al. 2005). (c) Cross-sectional SEM image of porous nanocrystalline (pnc) Si membrane imaged on the surface of a metalized silicon wafer revealing the cylindrical nature of the pores (Kavalenka et al. 2012)... 

Fig. 5.35 The surface of a PTFE membrane imaged at 5 kV in an FESEM exhibits a non-imiform series of rounded pores, and a three dimensional nature as the pores extend into the bulk membrane. The surface of the membrane appears wrinkled in texture but imaging at lower magnifications, after high magnification imaging, did not reveal picture frame contrast that would suggest this texture is due to beam damage. (From M. Jamieson, unpublished [162].)...

Microdialysis, Figure 4 (a) Microdialysis membrane sandwiched between two etched sets of silicon microchannels with Interdigitated sensing electrodes. Image taken from [10]. (b) Schematic of optical setup for phase separation polymerization to define the microdialysis membrane. Image taken from [ ]. (o) Schematic of crossed microfluidic channels separated by a nanoporous microdialysis membrane. Image taken from [12]... 

Figure 39.3 Flowsheet diagram of the Praxair process for oxy-coal combustion using membrane reactors based on O2 permeating membranes. (Image adapted from Ref. (57).)...

Figure 39.6 O2 permeation flux within a +25% CH4 +25% He thickness = 81 pm. Lao.6Sro.4Coo.8Gao203 a (LSCG) HF membrane (Image adapted from Ref. [117]. SEM micro-as a function of time using pure CO2, He, graphs adapted with permission from and CH4 as sweep gases for membranes. Elsevier.)...

Shown alongside the membrane image is the derived pore size distribution. Such distributions may be readily obtained using commercial image analysis software, either automatically or manually. 

Figure 6.16 AFC99 membrane imaged with a tip (left) and with a 4.2 im colloid probe (right). P-v=peakto valley Rms root mean square.

By using the appropriate software, image analysis ean be earried out to obtain different struetural parameters from the membrane images [79-82], for example, the surfaee pore density or number of pores per surfaee unit, Nj, the porosity or porous surfaee fraetion, , and the statistieal distribution of, for instanee pore areas, P, and pore perimeters, Pp, the equivalent or Feret pore diameter [83] ... 

FIG. 15 BET plots forthe A002 andTAMIUF membrane. Images of these membranes are presented in Figs 4 and 11, respectively. 

Membrane imaging techniques based on the measurement of the local solution conductivity using scanning ion conductance microscopes (SICM) have also been reported by Burnette and Ongpipattanakul, by Hansma et al., ° and more quantitatively by Baker group. A unique advantage of SECM relative to SICM is that the individual fluxes of different chemical species in a multicomponent solution may be determined by adjusting the electrochemical potential of the SECM tip to a value where the electroactive species of interest is reduced or oxidized. Since different chemical species have different electrochemical reduction potentials, it is possible to analyze for the individual membrane fluxes of several electroactive species in the same experiment. In addition, the use of selective SECM tips extends the SECM capabilities to the detection of fluxes of nonelectroactive species. 

For quantitative electrochemical analysis, the constant height SECM imaging mode should be preferred to the contact one. Figure 9.28 presents the iontophoretic transport of Fe(CN)/- across a track-etched PET membrane imaged at a 0.65 pm radius SECM-AFM Pt tip held at a constant... 

Dietz, R, Hansma, P. K., Inacker, O., Lehmann, H.-D., and Herrmann, K.-H. (1992). Surface pore structures of micro- and ultrafiltration membranes imaged with atomic force microscope. J. Membr. Sci. 65, 101. 

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