Fabrication of monoliths

Many of these steps include CVD, and CVD is now a major process in the fabrication of monolithic integrated circuits (IC), custom and semi-custom ASIC s, active discrete devices, transistors, diodes, passive devices and networks, hybrid IC s, opto-elec-tronic devices, energy-conversion devices, and microwave devices. 

The main feature of (meth)acrylate-based support materials is the broad diversity of monomers that is commercially available and that can thus can be used for the fabrication of monoliths. The resulting (meth)acrylate monoliths consequently cover a wide spectrum of surface chemistries and properties. The scope of monomers includes hydrophobic, hydrophilic, ionizable, chiral, as well as reactive (meth)acrylate building blocks [53]—the most popular being mixtures of butyl methacrylate and ethylene dimethacrylate (BMA/EDMA) or glycidyl methacrylate and ethylene dimethacrylate (GMA/EDMA) as cross-linker. 

The basic studies dealing with the preparation of continuous porous silica materials date back to 1991 [76-78]. Two years later, Nakanishi and Saga applied for a patent describing the fabrication of monolithic silica rods for chromatographic application [79-81], whereas a second protocol for the preparation of continuous silica rods was independently filed by Merck KGaA in Germany [82]. 

Figure 19 Continuous process for the fabrication of monolithic series connecting DSSC modules. (From Ref. 16.)...

An alternative to sintering frits, which deserves mention here, is to form frits via UV photopolymerization of a glycidyl methacrylate and trimethylolpropane trimethacrylate solution (UV radiation, 365 nm for 1 hour) [135]. The photopolymerization process is similar to that used in the fabrication of monolithic columns (Chapters 5 and 6). Frits fabricated with this method have shown to be reproducible since there is no sintering of packing material, weakening of the capillary column by removal of the polyimide coating and/or alteration of the stationary phase at the frit are avoided. 

The cross-linking reaction can take place at room temperature and thus these silicone polymers are useful for the fabrication of monolithic matrix systems for thermosensitive drugs. 

GaAs MMICs Monolithic microwave integrated circuits have been fabricated using ion implantation. This renders feasible the fabrication of monolithic phased array radars. These circuits incorporate active devices, RF circuitry, and bypass capacitors (53-54). 

The pressureless sintering method commonly used for the fabrication of monolithic silicon nitride ceramics cannot be successfully adapted for the fabrication of SiC fiber reinforced silicon nitride matrix composites because of significant strength degradation of currently available fibers at the high temperatures requir l for sintering, and also because of the problems associated with retardation of densification of the matrix material by the... 

J. T. Li and Y. Miyamoto, Fabrication of Monolithic TijSiCj Ceramic Through Reactive Sintering of Ti/Si/2TiC, Journal of Materials Synthesis and Processing 7 (2) (1999). 

A report from Kostiainen and coworkers utihzing ultra-TLC (UTLC) separations coupled with MALDI appears to offer significant improvement over high- performance TLC approaches. The fabrication of monolithic sUica UTLC plates provides a 10- to 100-fold greater sensitivity than HPTLC, a lower sample consumption, and a faster separation. Some caveats include less resolving power due to shorter elution distances (2 cm versus 5 cm) and a smaller overall adsorption surface area available for analytes. This method has been successfully applied to the analysis, purity estimates and qualitative idenhficahon components of crude mixtures of compounds synthesized via combinatorial chemistry [178]. Although at present TLC-MALDI analysis remains only semi-quanhtative in nature, its primary utQity as a qualitative tool for mixture separation and structural identification is currently on the rise. 

One must first consider general problems with respect to the application of surface nucleation in a technologically applicable process. When using surface crystallization in the fabrication of monolithic samples, sintering and... 

Xerogel monoliths are semiporous monoliths (usually 30-70% porosity). Yoldas [40] in the 1970s was the first to demonstrate fabrication of monoliths via a sol-gel process. Since then numerous routes for fabrication of xerogel silica monoliths and nonsilica monoliths were suggested and demonstrated. In this section a few examples of xerogel monolith febrication will be presented. 

Figure 3.76 (a) Continuous process for the fabrication of monolithic series connected dye-sensitised PV modules, (b) Schematic cross-section of the monolithic series connected dye-sensitised PV modules. Reprinted with permission from Kay and Gratzel, 1996. Copyright (1996) Elsevier... 

Li J T, Miyamoto Y, Fabrication of monolithic Ti3SiC2 ceramic through reactive sintering of Ti/Si/2TiC , J Mater Synth Proc, 1999 7 91-96. 

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