XPS provides answers to two significant issues that arise in studying electroactive polymers. First, what fraction of possible charge centers participates in the redox process? Second, what are the relative partition coefficients of two counterions that compete as charge-compensating counterions? To answer both these questions, we emersed (or immersed) poly(vinylferrocene) films from (or into) supporting electrolytes while maintaining potential control to govern the electrochemical history of the electroactive film. We found that all ferrocene units in the surface of a poly(vinylferrocene) film deposited on gold can be oxidized when the counterion is perchlorate, tetrafluoroborate, hexafluorophosphate, tosylate, or 1,5-naphthalenedisulfonate. In answering the second question, no internal standard was needed:  the concentration ratios of the two competing ions in both water and polymer phases were used as the experimental variables. For the completely oxidized ferricinium film, we found that the partition coefficient of perchlorate ions is 67% of that of fluoroborate ions.

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The attachment of anticancer agents to polymers is a promising approach towards reducing the toxic side‐effects and retaining the potent antitumour activity of these agents. A new tetrahydrophthalimido monomer containing 5‐fluorouracil (ETPFU) and its homopolymer and copolymers with acrylic acid (AA) and with vinyl acetate (VAc) have been synthesized and spectroscopically characterized. The ETPFU contents in poly(ETPFU‐co‐AA) and poly(ETPFU‐co‐VAc) obtained by elemental analysis were 21 mol% and 20 mol%, respectively. The average molecular weights of the polymers determined by gel permeation chromatography were as follows: Mn = 8900 g mol−1, Mw = 13 300 g mol−1, Mw/Mn = 1.5 for poly(ETPFU); Mn = 13 500 g mol−1, Mw = 16 600 g mol−1, Mw/Mn = 1.2 for poly(ETPFU‐co‐AA); Mn = 8300 g mol−1, Mw = 11 600 g mol−1, Mw/Mn = 1.4 poly(ETPFU‐co‐VAc). The in vitro cytotoxicity of the compounds against FM3A and U937 cancer cell lines increased in the following order: ETPFU > 5‐FU > poly(ETPFU) > poly(ETPFU‐co‐AA) > poly(ETPFU‐co‐VAc). The in vivo antitumour activities of all the polymers in Balb/C mice bearing the sarcoma 180 tumour cell line were greater than those of 5‐FU and monomer at the highest dose (800 mg kg−1). © 2002 Society of Chemical Industry

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