EPITAXIAL CRYSTALLIZATION AND CRYSTALLINE POLYMORPHISM OF POLY(1-BUTENE) - FORM I'

The hexagonal form I' of poly(1-butene) is epitaxially crystallized on 4-bromo and 4-chlorobenzoic acids, on the potassium salts of these ac ids, and on the hemiacid, potassium hydrogen 4-chlorobenzoate. The con tact plane in all cases is (11.0). In form I', the successive (11.0) p lanes contain, alternately, only left-hand or only right-hand helices. The observed epitaxies can therefore be differentiated according to t he chirality of the helices in interaction with the substrate. Epitaxi es are governed by a one-dimensional match which involves the intertur n distance, i.e. the distance between successive outer helical paths. For less specific interactions, appropriate tilts of the helix axis he lps achieve matching with the substrate lattice periodicities.