Tunable properties of inclusion complexes between amylose and polytetrahydrofuran.

Amylose and polytetrahydrofuran (PTHF) are mixed in an aqueous solution to form inclusion complexes. DSC shows that immediate mixing results in complexes having lower melting temperatures compared with complexes prepared with longer mixing times. The washed complexes melt at higher temperatures compared with the corresponding unwashed complexes. XRD indicates that amylose-PTHF complexes diffract similar to amylose-fatty acids complexes (V6I -amylose helices), with additional diffractions correlating with amylose-alcohol complexes (V6II -amylose helices). This suggests that the structure of amylose-PTHF complexes is an intermediate or a mixture between V6I - and V6II -amylose. This shows that, besides residing inside the amylose helices, some PTHF chains are located in between the amylose helices.