Attachment of bis-(trifluoromethyl)aryl labels onto the chain ends of poly(ethylene terephthalate) (PET) track-etched membranes and films by surface wet chemistry

Organic chemistry performed at the solid-liquid interface allowed us to achieve the selective chain-end functionalization of poly(ethylene terephthalate) (PET) membranes and films with perfluorinated labels. The carboxyl endings were activated with water-soluble carbodiimide and were coupled to 3,5-bis(trifluoromethyl)benzylamine (1) in aqueous acetonitrile, whereas the hydroxyl endings were activated by tosylation and were also coupled to 1. 3,5-Bis(trifluoromethyl)phenyl isocyanate (2) was directly fixed on the hydroxyl endings of the polymer substrates in dry organic media. All the derivatized materials were analyzed by X-ray photoelectron spectroscopy, allowing the quantitative determination of the amounts of surface-grafted labels. Yields were between 10 and 100 pmol/cm(2). These surface reactivity assays mimic at best the experimental conditions that would be applied for the covalent anchorage of biologically active molecules onto PET substrates used in cell culture systems. (C) 2000 John Wiley & Sons, Inc