are considered to behave as a liquid-crystalline polymer (Cameron & Donald, 1992; Jenkins et al., 1993; Waigh et al., 2000a). In the presence of water, plasticization of amylopectin branch points, which act as flexible spacers, allows the double helices to be decoupled from the polymer backbone and aligned into lamellar register, resulting in a transition from the nematic (disarranged) to smectic (aligned) phase (McArdle, 1989; Fig. 1.4). In the absence of water, the branch points become less flexible, pulling the double helices out of register and leading to the development of a nematic phase, in which the long range correlation between the layers is lost. However, correlations persist within the double helices, which give rise to diffraction peaks in wide-angle X-ray patterns (Waigh et al., 1998).
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