Examples of hydrophobic groups include alkyl groups (of the general formula Cn H2n+1 --) having greater than about 6 carbons to about 20 carbon atoms, such as octyl, nonyl, decyl, undecyl, dodecyl, etc. as well as cyclic (i.e. cyclohexyl) and aromatic groups such as phenyl, tolyl, and arylalkyl groups such as nonylphenyl and t-octylphenyl.