Wetting microchannel

We prepared microchannel reactor employing stainless steel sheet 400tan thick patterned microchannel by a wet chemical etching. The microchannel shape and dimension were decided by computer simulation of flow distribution and pressure drop of the reactants in the microchaimel sheet. Two different types of patterned plates with mirror image were prepared [5]. The plate has 21 straight microchannels which are 550/an wide, 230/an deep and 34mi long as revealed in Fig. 1(b). 

The surfactant type (anionic, nonionic) is indifferent [39], but cationic surfactants should be avoided to produce OAV emulsions because they lead to complete wetting of the dispersed phase on the microchannel plate. 

FIGURE 2.7 Etch profiles of microchannels obtained by wet etching (a) and dry reactive ion etching (b). In (a), the more rounded profile was obtained with direct wet etching using a PDMS channel mold (50 im in width), whereas the trapezoidal profile (dotted curve) was made with the deposited nickel layer as the etch mask (150 im in width) [125]. Reprinted with permission from Elsevier Science. 

Kikutani, Y., Hisamoto, H., Tokeshi, M., Kitamori, T., Micro wet analysis system using multi-phase laminar flows in three-dimensional microchannel network Lab-chip 2004, 4, 328-332. 

Figure 1.1 Wet chemically etched microchannels in a stainless steel foil.

Figure 1.11 Photo of an arrangement of wet chemically etched microchannel foils. Owing to misalignment, in some layers the microchannels are not formed correctly to elliptically shaped channels.

Figurel.12 Photo oftwo wet chemically etched foils arranged and aligned correctly to form nearly circular microchannels.

Figure 1.15 Sol-gel generated catalyst support layer inside rectangular stainless steel microchannels. The support layer (dark line in photo) surrounds the microchannels completely, providing a porous system to be wet impregnated.

Figure 14 Fabrication procedure for the pile-up microreactor. (1) Photolithography Conventional photolithography/wet etching methods were applied. The back side of the glass plate was covered with polyolefin tape during the HF treatment. (2) Drilling Penetrating holes were drilled at the inlet and outlet ports of the micro-channel circuit. (3) Thermal bonding The required number of glass plates with microchannels and one cover plate were laminated and bonded thermally at 650°C.

SAMs on microchannel walls have been studied for surface properties in microreactors,59 to control surface wetting,60 to create zones for specific immobilization of proteins and biomolecules,61 and to conduct catalytic reactions.62 And a pH sensing monolayer confined to a glass microchannel has been reported by our group.32... 

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