Glasses surface modifications

Lin, C. H., Lee, G. B., Fu, L. M., and Chen, S. H. (2004). Integrated optical-fiber capillary electrophoresis microchips with novel spin-on-glass surface modification. Biosens. Bioelectron. 20, 83—90. 

In the presence of polyethylene oxide MW 300,000 at a concentration of 0.025 g liter , variations in pH and ionic strength have no effect on elution volumes and a single calibration curve is obtained as shown in Figure 4 and Table II. This behavior presumably also results from modification of the glass surface by the polyethylene oxide surfactant, but in this case charge effects appear to be completely suppressed and the effective pore diameter and volume reduced. Such an interpretation is also in accord with the fact that the elution voliomes are lower with polyethylene oxide than with Tergitol, since Tergitol is a much smaller molecule than the polyethylene oxide. 

Solutions to the above problea are required if efficient open tubular colunns are to be prepared. The energy of the saooth glass surface can Sse Increased by roughening or chemical Modification, or the surface tension of the stationary phase can be lowered by the addition of a surfactant. Roughening and/or cheMical modification etre the most widely used techniques for column preparation the addition of a surfactant, although effective, modifies the separation properties of the stationary phase and may also limit the thermal sted>ility of columns prepared with high temperature stable phases. 

Surface modification reactions are used to improve the wettability of glass surfaces by polar stationary phases and to Improve the extent of deactivation by sllylation" [138-146,166]. Miaaiuua procedures have been investigated but only a few are in use. Of these, the most important reactions are etching by hydrogen chloride, leaching with aqueous hydrochloric acid, formation of whiskers and solution deposition of a layer of solid particles. Because of the high purity and thinness of the... 

Surface Modification. A polydiene film (supported on a microscope slide) was immersed in a stirred, room temperature, RTD-acetonitrile solution of known concentration contained in a large glass-stoppered test tube. After a specific reaction time, the film was removed from the solution, washed with acetonitrile, water, and acetonitrile again, and dried under vacuum (Step 1). Films subsequently treated with base were immersed in aqueous solutions for 5-15 min. They were then washed with water and CH3CN, and vacuum dried (Step 2). Some films were aged in air at room temperature. 

Yazawa, T., H. Nakamichi, H. Tanaka and K. Eguchi. 1988. Permeation of liquid through a porous glass membrane with surface modification. Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi 96(1) 18-23. 

Figure 3. Reaction schemes for modification of the glass surface by the azidofunctional alkoxysilane (reaction 1) and reaction of the modified glass surface with the polyethylene matrix (reaction 2).

The first contact-killing surface was described by Isquith et al., who modified glass substrates with the silane 3-(trimethoxysilyl)-propyldimethyloctadecylammonium chloride, often referred to as DOW5700 [39], However, the claim was made on the basis of the DOW suspension test (see Sect. 2.2), which cannot distinguish between biocide release and contact activity. In subsequent work, neither the original authors nor followers proposed a working model for a mechanisms that was able to explain the contact activity of this surface modification. The first model for contact activity was proposed in 2001 (see Fig. 5) [40],... 

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