Surface-selective introduction of specific functionalities onto poly(tetrafluoroethylene)

Abstract

Exposure of poly(tetrafluoroethylene) film samples to Me2SO solutions of the potassium salt of benzoin dianion renders metallic gold-colored, air-sensitive film samples. The color and property changes of the film are due to a carbonaceous reduction product, the thickness of which can be controlled by the duration of the exposure to benzoin dianion. Reduced layers of ca. 150-20000 A have been prepared. The chemical structure of the carbonaceous product is complex: it is a cross-linked polymeric carbon containing carbon-carbon single, double, and triple bonds, fluorine and hydrogen bound to sp2 and perhaps sp3 carbon, and a small amount of oxygen. Reduced film samples react with a range of reagents which are reactive toward unsaturation. Strong oxidants completely remove the reduced layer. Chlorine and bromine react readily, turning gold-colored films white and pale yellow, respectively. The reduced layer can be used as a reactive "handle" to incorporate hydroxyl, amino, and carboxylic acid functionalities on the surface of poly (tetrafluoroethylene): Hydroboration followed by oxidation introduces hydroxyl groups. Maleic anhydride adds radically and can be hydrolyzed to carboxylic acids. Substitution reactions of brominated films introduce amino groups.

Surface Modification of Halogenated Polymers. 8. Local Reduction of Poly(tetrafluoroethylene) by the Scanning Electrochemical Microscope − Transient Investigation

“…The combination of (5), (6), and (9) then leads to a simple approximate time variation for h red and r red According to this simple model, the experimental variations of the reduced zone dimensions with the redox mediator concentration [P] result from eq 10 as (1 + )D red C red should be proportional to i red , which is itself proportional to [P]. It implies that the concentration of the reduced charge in the reduced PTFE, C red , is proportional to [P].…”

Stimulation of Cell Adhesion at Nanostructured Teflon Interfaces

“…On the one hand, reactive groups can be introduced by procedures like plasma treatment, [ 2 ] UV treatment [ 3 ] and/or chemical reduction. [ 4 ] On the other hand, one can take advantage of non-covalent immobilization by unspecifi c adsorption. [ 5 ] Besides their advantages, both methods share common disadvantages as they are either limited to specifi c biomolecules and harsh procedures or they lack stability and control of biomolecule conformation.…”

Hydrocarbon Oligomers

“…X-Ray diffraction [37], electrical conductivity [36], UVjVIS spectra [34] and solid state I3C-NMR studies [30] indicate a superposition of graphitic, diamond-like and also carbynoid structures for the products derived from dehalogenation of PTFE. Carbynes are further characterized by IR-spectroscopy [27, 281, especially by the C-C stretching mode (vCGc) at 2100-2200 cm-'.…”