The chain folding behavior of oxyethylene/oxybutylene (E/B) diblock co
polymers, with one crystallizable E block and one noncrystallizable B
block, has been studied by simultaneous SAXS and WAXS, low-frequency R
aman spectroscopy, and differential scanning calorimetry. Two models,
normal density (ND) and crystal/liquid-crystal (CLC) models were used
to explore the results, consideration being given to the difference in
the cross-sectional area of the two chains and the need to fill space
at approximately normal density. It was found that both models can de
scribe the data for the longer copolymers, but the CLC model is better
for the shorter copolymers.