. "A modified particle is disclosed wherein a particle has an attached group having the formula: wherein Ar represents an aromatic group; R1 represents a bond, an arylene group, an alkylene group, wherein R4 is an alkyl or alkylene group or an aryl or arylene group; R2 and R3, which can be the same or different, represent hydrogen, an alkyl group, an aryl group, ???OR5, ???NHR5, ???NR5R5, or ???SR5," . . . . .