Chemical Fabrics and Film Association

Chemical Company of Malaysia Berhad, See CCM Chemicals Sdn Bird (Malaysia), 191 Chemical Databases Software, 308 Chemical Fabrics and Film Association, 269 Chemical Industries Association (CIA), 265 Chemical Industry Institute of Toxicology (CUT), 269 Chemical Institute of Canada (CIC), 259 Chemical Lime Co., 223... 

Many of the unique properties of siUcone oils are associated with the surface effects of dimethylsiloxanes, eg, imparting water repeUency to fabrics, antifoaming agents, release liners for adhesive labels, and a variety of poHshes and waxes (343). Dimethylsilicone oils can spread onto many soHd and Hquid surfaces to form films of molecular dimensions (344,345). This phenomenon is greatly affected by even small changes in the chemical stmcture of siloxane in the siloxane polymer. Increasing the size of the alkyl substituent from methyl to ethyl dramatically reduces the film-forming abiUty of the polymer (346). The phenyl-substituted siUcones are spread onto water or soHd surfaces more slowly than PDMS (347). 

The increasing importance of multilevel interconnection systems and surface passivation in integrated circuit fabrication has stimulated interest in polyimide films for application in silicon device processing both as multilevel insulators and overcoat layers. The ability of polyimide films to planarize stepped device geometries, as well as their thermal and chemical inertness have been previously reported, as have various physical and electrical parameters related to circuit stability and reliability in use (1, 3). This paper focuses on three aspects of the electrical conductivity of polyimide (PI) films prepared from Hitachi and DuPont resins, indicating implications of each conductivity component for device reliability. The three forms of polyimide conductivity considered here are bulk electronic ionic, associated with intentional sodium contamination and surface or interface conductance. 

The poly(ether/amide) thin film composite membrane (PA-100) was developed by Riley et al., and is similar to the NS-101 membranes in structure and fabrication method 101 102). The membrane was prepared by depositing a thin layer of an aqueous solution of the adduct of polyepichlorohydrin with ethylenediamine, in place of an aqueous polyethyleneimine solution on the finely porous surface of a polysulfone support membrane and subsequently contacting the poly(ether/amide) layer with a water immiscible solution of isophthaloyl chloride. Water fluxes of 1400 16001/m2 xday and salt rejection greater than 98% have been attained with a 0.5% sodium chloride feed at an applied pressure of 28 kg/cm2. Limitations of this membrane include its poor chemical stability, temperature limitations, and associated flux decline due to compaction. 

Figure 1 illustrates the various layers and chemical reactions associated with the sensor developed in our laboratories. We chose to mass-produce this type of sensor by developing a fabrication scheme that utilized thin/thick film cleanroom processing techniques similar to those used in the integrated circuit industty. The sensors were fabricated in batches of 112, although this number can be easily increased and the process automated. This approach was intended to address the problem responsible for the absence of an implantable glucose sensor from the market, namely the inability to mass-produce a reliable, reproducible, and economical disposable sensor. 

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