The instant invention relates to a composition comprising a) an organic material which is susceptible to oxidative, thermal or light-induced degradation, and b) at least one compound of the formula (I) wherein the general symbols are as defined in claim 1; especially wherein at least one of the radicals R2, R3 or R4 is —CH2—CH(CH3)—S(O)p—R12, —CH2—CH2—CH2—S(O)p—R12, —CH2—CH(R11)—CH2—R12 or —CH2—CH═CH—R12, R11 is hydrogen or halogen, R12 is a monovalent perfluorinated alkyl or alkenyl, linear or branched organic radical having four to twenty fully fluorinated carbon atoms; or —CH2CH2(CF2)mCF3, m is 3 to 12, and p is 0, 1 or 2. The compounds of the formula I are useful as reducers of surface energy for organic materials, for example synthetic polymer. Polymers with such a reduced surface energy possess an “easy-to-clean”, “self-cleaning” “antisoiling”, “soil-release” “antigraffiti”, “oil resistance”, “solvent resistance”, “chemical resistance”, “self lubricating”, “scratch resistance”, “low moisture absorption”, “dirt pickup resistance”, “slip properties” and “hydrophobic surface”; and anti-adhesion properties against proteins and against microorganism such as for example bacteria, fungi and algae.