Adsorption solutes onto silanized glass

Eklund, T. et al., Investigation of the adsorption of mono- and bifunctional silanes from toluene onto porous silica particles and from aqueous solutions onto E-glass fibers, in Silanes and Other Coupling Agents, Vol. 2, K.L. Mittal, Ed., VSP BV, Zeist, 2000, 55. 

Fig. 4 (a) The reactive-ester analogue of a carboxy-terminated monochloro-silane derivative self-assembles onto a glass substrate to result in a reactive monolayer, (b) Onto this, an ethyleneimine-containing polymer coil, obtained by the partial conversion of a polyoxazoline precursor polymer binds covalently after adsorption from solution to give a stable polymer cushion for the binding of a monolayer of a reactive amphiphile, a reactive ester derivative of a fatty acid in the example given in (c)... 

With very low concentrations of analyte, adsorption onto glass surfaces becomes a problem. This problem is best avoided by silanizing the glassware before use. A suitable method is to soak the glass in a 10% solution of dichlorodimethylsilane in toluene for 1 h, rinse with dry toluene and then with methanol. The silane forms dimethylsilyl bridges between adjacent hydroxyl groups on the glass surface, and the methanol converts the chlorine atom of... 

Figure 6. Schematic representation of the adsorption of silane coupling agent molecules onto glass fiber surface. A) The silane solution is a low concentration below the onset of association, and B) the silane solution is a high concentration above the onset of association. Open cirde indicates isolated silanes whereas the closed circle denotes hydrogen bonded or oligomeric silanes. Note the disturbance in packing is created at a high concentration.

Silane coupling agents adsorb onto the surface of glass fibers as multilayers. The amount of adsorbed silane is a function of the concentration of silane treating solutions. Since the mechanical properties of FRP have some correlations with the amount of coupling agent present, it is important to determine the concentration dependence of the silane adsorption. Johannson eJt reported the first correlation using C-labeled Y MPS. 

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