Figure 5. A proposed mechanism for the formation of the arrays of semi-crystalline lamellae in amylopectin.

C and A indicate the crystalline and amorphous lamellae. The purple shaded regions indicate the nascent SL space where non-lamellar amylopectin chains, amorphous in nature, are being formed. Types of chains: (1) single-lamella (SL) chains that are (mostly) confined in crystalline lamellae (grey lines); (2) type-1 TL chains, crystalline-lamella-connecting chains, which span more than one crystalline lamellae (red lines); (3) type-2 TL chains, non-lamella-connecting chains, which protrude the SL space but remain in the amorphous lamellae (blue lines). The longest chain length confined to a crystalline lamella, predicted from Figure 2, is X ∼ 31 (i.e. chains ≥32 enters the contiguous amorphous lamella), while longer SL chains (red lines) with X ∼ 60–70 are sufficiently long to participate in crystalline formation in the subsequent crystalline lamella.