Glass surface pretreatment

Helmuth DW, Ghiasuddin SM, Soderlund DM (1983) Poly(ethylene glycol) pretreatment reduces pyrethroid adsorption to glass surfaces. J Agric Food Chem 31 1127-1129... 

Open-tubular column Soda-lime glass capillaries were treated with a sodium hydroxide aqueous solution at 45-50 "C for 2 days and washed with methanol until the effluent became neutral. The capillaries were then dried under helium at 120 "C for a few hours and washed with methanollc 0.01 H hydrochloric acid, water and methanol. Finally, the capillaries were dried mder helium at 120 °C for a few hours. Chemically and physically stable silica gel layer was formed on the glass surface with above pretreatments. An orgwic solution of octadecyltriethoxysilane was filled into the pretreated capillaries and the reaction weis carried out at elevated temperature. After the reaction, columns were washed with orgcuiic solvents and the mobile phase. Both ends of columns were inserted into narrow-bore(ca. 0.2 mm i.d.) PTFE tubing for small dead-volume connection. 

Effect of surface pretreatments upon the photolysis of 2-pentanone adsorbed on Vycor glass at 298 K... 

Surface - smooth metals, plastics, ceramic, glass depending on manufacturing and surface pretreatment... 

Adhesion promoters. Sometimes referred to as coupling agents, these additives have the ability to enhance resin adhesion to surfaces such as glass or metals(8). The most popular type are silanes which can either be mixed with the adhesive itself or applied to the substrate as a primer. They will be further considered in Chapter 3 under adhesion and surface pretreatment. 

There are a number of materials used for the fabrication of pTAS devices. Perhaps the most common is glass due to its low cost, ease of machining, and suitability for electrophoresis and electroosmotic flow (EOF) applications without requiring surface modifications. It is also chemically inert to most reagents (apart from hydrofluoric acid and concentrated alkali). Silicon is also a valuable material that has similar chemical inermess and can easily be machined by chemical etching. While it is more expensive, it can be easily chemically etched to yield far higher aspect ratios than are possible with glass. Silicon is not suitable for electrophoresis or EOF applications without surface pretreatment. Devices fabricated from polymers such as polymethylmethacrylate (PMMA) and polydimethylsiloxane (PDMS) are also frequently used due to the low cost of the material (especially important for disposable devices) and the ease of fabrication. Perhaps one drawback with polymers is their incompatibility with solvents. They are suited to electrophoretic applications but frequently require surface modification to support EOF. Occasionally, metals are used however, these are far more frequently encountered in chemical microreactors. 

Type 3 (Thin Type) Fimbriae. Filaments of this type are restricted to Klebsiella and Serratia marcescens. They differ from type 1 fimbriae in that they are thinner (4.8 nm in diameter) and more numerous. They are characterised by a strong MR adhesion to fungal and plant cells and to glass surfaces. Type 3 fimbriae are incapable of binding to erythrocytes or animal cells, imless pretreated with tannin. 

Formvar solutions are placed in any tall glass container that has a lid. Clean glass slides, pretreated with a detergent to aid release of the cast film, are dipped into the solution and then quickly lifted up above the solution, covered and permitted to dry slowly in the solvent vapor. To free the film, the glass slide is scored around the perimeter with a razor, scalpel or needle. The film may then be floated onto a water surface and the grids placed on it and picked up, as for col-... 

Un-OH can also be copolymetized with propene on a MAO-pretreated glass surface by Et(Ind)2ZrCl2. Parts of the resulting copolymer are chemically bonded to the surface, as shown by extraction experiments, scanning electron microscopy (SEM) microscopy as well as Fourier transformation infrared spectroscopy (FUR) analysis. Similar results were reported for the copolymerization of ethene with Un-OH by the same catalyst system on the organically modified silicate montmorillonite (OMMT) resulting in PE-Un-OH/OMMT nanocomposites which consist of well-exfoliated OMMT dispersions and controlled degrees of PE functionalization. ... 

Figure 8.7 Effect of immersion in water at 40 °C on the tensile lap-shear strength of glass fibre reinforced plastic (GRP) substrates bonded with a two-part acrylic adhesive [40]. The surface pretreatment was simply an abrasion/solvent-cleaning process.

The two types of tooth-colored material, namely, the composite resin and the glass-ionomer cement, are described, together with their current variations. Composite resins are bonded with specific bonding agents, and this technology has advanced rapidly over the last 10 years or so. Surface pretreatment is critical for the success of these systems and the current state of the understanding of this aspect of the subject is described. 

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