POLYMERIZATION OF CYCLIC IMINO ETHERS .7. USE OF SESSILE DROP METHOD TO INVESTIGATE SURFACE STRUCTURE OF POLY (N-ACYL AND AROYL ETHYLENEIMINES)

Critical surface tensions (γe) of a series of crystalline poly (N-acyl ethyleneimines) and poly(N-benzoyl ethyleneimine) were measured. The polymers with aliphatic side chains had γe dropping from 24.5 to 22 dynes/cm as the side chain lengthened from butyryl to stearoyl. This shows that the surfaces of the polymers comprise close packed methyl groups, a possibility consistent with X-ray data. A similar result was shown for a jointed fluoro-hydrocarbon side chain, {A figure is presented}, where γc was 11 dynes/cm, confirming a perfluoro-methyl surface there. Poly(N-benzoylethyleneimine) had a very low γe of 25.5 dynes/cm. This is attributed to a surface which exposes benzene ring faces, and consequently π-electrons. © 1969.