Introduction of carboxylic acid, aldehyde, and alcohol functional groups onto the surface of poly(chlorotrifluoroethylene)

Carboxylic acid, aldehyde, and alcohol functionalities have been independently introduced to the surface of poly(chlorotrifluoroethylene) by using two step modification sequences: Li reagents containing protected functional groups react with polymer film surfaces via a surface-selective reduction--addition--elimination sequence which incorporates the protected functional group on the surface of the polymer. Deprotection renders polymer film samples containing surface-confined functional groups. Carboxylic acids were introduced using 2-(lithiomethyl)-4,4-dimethyloxazoline, aldehydes were introduced using 2-lithio-1,3-dithiane, and alcohols were introduced using acetaldehyde 3-lithiopropyl ehtyl acetal. The depths of the modification reactions were sensitive to solvent and temperature and could be controlled. The depth of reaction was also dependent on the Li reagent and varied according to acetaldehyde 3-lithiopropyl ethyl acetal > 2-lithio-1,3-dithiane > 2-(lithiomethyl)-4,4-dimethyloxazoline; the carboxylic acid functionalization reaction is the most surface selective. The carboxylic acid site density was determined using exp 14 C-labeled (two-position) 2-(lithiomethyl)-4,4-dimethyloxazoline. 10 ref.--AA