Polysiloxanes with 3-(alkyldimethylammonio)propyl pendant groups were synth
esized by quaternization of n-octyldimethylamine or n-dodecyldimethyl amine
with linear polysiloxanes containing 3-chloropropyl groups and/or 3-bromop
ropyl groups attached to silicon atoms. The precursor polysiloxanes, poly[(
3-chloropropyl)methylsiloxane] homopolymer and various copolymers containin
g (3-halogenopropyl)methylsiloxane and dimethylsiloxane units, were obtaine
d by equilibrium cationic polymerization of linear and cyclic siloxanes wit
h (3-halogenopropyl)methylsiloxane units. The polysiloxanes bearing quatern
ary ammonium salts (QAS) showed bactericidal activity against bacteria such
as Escherichia coli and Aeromonas hydrophila when incorporated in a polysi
loxane network. The activity was retained after 66 days of immersion in wat
er. The QAS-containing polysiloxanes are also active in aqueous solution. (
C) 2000 John Wiley & Sons, Inc.