Smooth surfaces PDMS surface

Patterned zeolite films have been investigated for possible optical, magnetic, and electronic applications. Zeolite nanocrystals have been used as building blocks for patterned films.[140] Silicalite-1 nanocrystals were synthesized hydrothermally and the resulting crystals, after redispersion in ethanol, were deposited onto a smooth surface, such as a silicon wafer. A polydimethylsilane (PDMS) stamp was applied with adequate... 

A microchannel valve having smooth surface and the stacked PDMS stractures were fabricated (Fig. 5.14). Underneath the microchannel, a membrane and a pressure applying chamber are formed. The depth of microchannel of 50 pm and the membrane thickness of 60 pm were considered. For a 300 pm x 500 pm square membrane, it was numerically identified that more than a 150 kPa pressure was needed to obtain the deflection of 50 pm, which can close the microchannel perfectly. 

The concept of polymer-based 3D microstructure utilizes replica molding. Therefore, the key fabrication processes include 3D mold fabrication and pattern transfer. The material property is a very important factor when choosing the polymer and mold materials for special applications. For easy handling and accurate shape transfer, the mold requires smooth surface and relatively low thermal expansion coefficient since the curing of the polymer often involves heat. Nowadays, several polymer materials such as PDMS, PMMA, and SU-8 are popular choices for microfluidic applications. 

R( (ion has studied the dewetting of ultra-viscous PDMS on ideal surfaces (Figure 7.9). She showed that on such smooth and passive surfaces, a highly viscous fluid slides. 

Wetting States on Model Rough PDMS Surfaces. The surface properties of all model bumpy and cavity PDMS surfaces were studied by static and dynamic contact angle measurements with water as the test liquid and the data are tabulated in Table 4.3. The contact angle data for the smooth PDMS surface are included as reference. As discussed in Sect. 4.1, wetting of liquid on a rough surface can be described by... 

---