1829dehydes, and carboxylic acids). The strategy involves protecting-group chemistry. Carboxylic acids have been introduced by using the chemistry in eq 3. Acknowledgment. We are indebted to Dr. Ralph G. Nuzzo and AT&T Bell Laboratories for assistance in obtaining ESCA spectra and the Office of Naval Research for financial support.Registry No. PCTFE, phenyllithium, methyllithium,. A 310 430 nm Figure 4. UV-vis spectra of PCTFE oil (0), PCTFE oil after reaction (0.5 equiv) with methyllithium (O'), PCTFE film (F), and PCTFE film after reaction (5 min) with methyllithium (F').The surface modification reaction appears to be less surface selective than the two-phase dehydrofluorination of poly(viny1idene fluoride)? it does not, however, exhibit autocatalysis and pitting. If the stoichiometry in eq 2 is assumed, the mass losses at 2-, lo-, and 20-min reaction times correlate with average reaction depths of 45,136, and 285 A, respectively. The contact angle data further suggest that the reaction is not surface selective: changes within the sampling depth (several angstroms) of this technique are occurring after an average of many tens of angstroms of material have reacted.Work in progress concerns extending this chemistry to introduce surface polar functional groups (alcohols, al- I OH References and Notes(1) For a discussion of the theory of chemistry in reduced dimensions, see: Astumian, R. D.; Schelly, Z. A. J. Am. Chem. SOC. 1984, 106, 304. (2) For a discussion of chemistry in noninteger dimensions between two and three. see: Pfeifer. P.: Avnir. D.ABSTRACT Complex formation between poly(acry1ic acid) (PAA) and poly(oxyethy1ene) (POE) was studied by following changes in the emission of dansyl-labeled PAA (Dan-PAA). Addition of POE with a molecular weight of 24000 (POE-24) to Dan-PAA produced an up to eightfold increase of fluorescence with a blue shift of the maximum. Addition of much higher molecular weight POE led to a relatively small increase of fluorescence, and the emission maximum was red-shifted, suggesting increased exposure of the dansyl label to water. This was interpreted as indicating that Dan-PAA stretched out and was in contact with POE only at widely separated regions. The model was supported by the observation that addition of POE-24 to the Dan-PAA complex with high molecular weight POE leads to emission changes similar to those seen when POE-24 is added to Dan-PAA alone. Also, displacement of Dan-PAA from POE complexes by unlabeled PAA leads first to a sharp drop but later to an increase of fluorescence, indicating that Dan-PAA is first liberated in a stretched state before contracting to its equilibrium extension. An acrylic acid copolymer with 9 mol % acrylamide forms POE complexes similar to those of PAA although polyacrylamide does not complex with POE. This suggests than an uninterrupted sequence of interacting groups is not important in the formation of PAA-POE complexes.