AN INVESTIGATION ON FOLD STRUCTURE IN POLYETHYLENE LAMELLA WITH DIAMOND LATTICE MODEL

摘要

Based on perfect rotational isomeric state model of polyethylene chainwithout any torsional stretch or chain twisting, the separation distance between a zig-zagsegment and its re-entry ones in lamella has been investigated. The intervals were definedby a pair of quantum numbers （kx, ky） according to the formula: D=0.153/(31/2)(（8kx2+16ly2）1/2)（nm）kx and ky are integers just as the lattice coordinates on the respective & and α- axes ofthe crystal lattices for polyethylene. The crystal lattices of polyethylene can be accessibleby the re-entry stems, whether it is adaceni fold or not. Conformations, until 14-bondfold, of the fold part were investigated. The sequence TTGTTG’ G’ TTGGTTG possessesthe lowest average conformation energy per bond for （110） fold, and TGTTG’G’TTTG’for （020） fold, TTTGGTGGTTGTG’ etc. for （200） fold.