2-DIMENSIONAL ARRAY OF POLY(METHACRYLIC ACID) BRUSHES ON GOLD SUBSTRATES - INTERACTION WITH FERROCENE-TERMINATED POLY(OXYETHYLENE)S

Polymeric amphiphiles (1(n)), consisting of a poly(methacrylic acid) ( PMAA) segment (segment length, n = 35 and 63) and two long alkyl chain s whose ends are modified with disulfide, form self-assembled monolaye rs on gold electrodes. The lateral molecular distribution within the m onolayers is successfully controlled by varying the conformational siz e of the PMAA segments during assembling. Ferrocene-terminated poly(ox yethylene)s (2(m)), having various chain lengths (m = 10-120) are prep ared and used as guest polymers. Host-guest interactions of 2(m) and t he 1(n) monolayer-covered gold electrodes can be monitored electrochem ically by means of electron transfer of the ferrocene moiety. The amou nt of adsorbed 2(m) gives a maximum when the chain length of guest 2(m ) (m) matches that of host 1(n) monolayer (n). When the lateral molecu lar distribution in the monolayer brushes is controlled to be most fav orable for the guest polymers, a 1:1 host-guest polymer complexation c an be accomplished. FTIR spectroscopic data suggest that such complexa tion results from multiple hydrogen bonding between the COOH groups an d the ether oxygen atoms.