The colloidal stability of random (P[SBMA]) and core-and-shell (PS/PBMA) copolymer latexes of styrene and butyl metacrylate is modified, after exposure to toluene, chloroform, benzene, and heptane vapors, This effect is observed using turbidimetric latex titration with NaCl, as well as observing latex settling after 48 h exposure to NaCl. We propose that this may be due to one or both of the following factors : (i) a change in the Deborah number, which is in turn due to a change in the viscoelastic properties of one or more particle domains, induced by apolar solvent sorption; (ii) a change in the extension of charged polymer chain-ends (polymer hairs), toward the aqueous phase.