SynopsisThe morphology of poly(ether esteramide)s (PEEA) of the general formula [(6NT6)k -PTMO]= has been investigated by wide and small angle X-ray scattering and electron microscopy techniques. The copolymers are based on poly(esteramide) "hard" segments (containing an average number k of 6NT6 consecutive units) alternating poly(tetramethy1ene oxide) (PTMO) "soft" segments of constant length (MW -900). The fraction of crystallized 6NT6 increases by increasing the PTMO content (i.e., by lowering k ) , approaching unity fork -1. The morphology is of lamellar type, with both thickness and width of the crystalline domains (6NT6) decreasing with the increase of PTMO content; in the interlamellar amorphous regions both "soft" and "hard" segments tend to segregate in separate domains. For k = 1, crystalline domains, formed essentially by isolated 6NT6 mits, alternate with amorphous PTMO interlayers. The mechanism of evolution of the morphological structure as a function of the copolymer composition is discussed.