Kim Eunju, Uyama Hiroshi, Doi Yoshiharu, Ha Chang-Sik, Iwata Tadahisa
Department of Polymer Science and Engineering, Pusan National University, Pusan 609-735, Korea.
Macromol Biosci. 2005 Aug 12;5(8):734-42. doi: 10.1002/mabi.200500038.
Solution-grown, chain-folded lamellar crystals of poly(16-hexadecalactone) (PHDL) were crystallized isothermally from 1-hexanol at 70 degrees C. The morphology of lozenge-shaped crystals was studied by TEM and AFM. The lamellae are ca. 10 nm thick and the chains run orthogonal to the lamellar surface with folding along (110) and (110) planes. The crystal structure of PHDL was determined by XRD and election diffraction of single crystals. The chains are in the 2(1) helix conformation close to all-trans and the structure consists of an orthorhombic unit cell with a P2(1)2(1)2(1) space group with the lattice constants a = 0.746 +/- 0.001 nm, b = 0.504 +/- 0.001 nm, and c (chain axis) = 4.116 +/- 0.003 nm. There are two chains per unit cell, which exist in an antiparallel arrangement. Molecular packing structure has been studied in detail, taking into account both diffraction data and energy calculations. The setting angles, with respect to a axis, were +/-40 degrees for the corner and center chains, respectively. By using the electron and XRD data, the best molecular packing model was refined to R-factors of 0.168 and 0.196, respectively. A brief comparison of chain-packing structure is also made with related polymer structures.
通过溶液生长法，在70℃下从正己醇中使聚（16 - 十六内酯）（PHDL）的链折叠层状晶体等温结晶。通过透射电子显微镜（TEM）和原子力显微镜（AFM）研究了菱形晶体的形态。片晶厚度约为10nm，链垂直于片晶表面排列，并沿（110）和（110）平面折叠。通过X射线衍射（XRD）和单晶电子衍射确定了PHDL的晶体结构。链呈接近全反式的2(1)螺旋构象，结构由具有P2(1)2(1)2(1)空间群的正交晶胞组成，晶格常数a = 0.746 ± 0.001nm，b = 0.504 ± 0.001nm，c（链轴）= 4.116 ± 0.003nm。每个晶胞中有两条链，它们以反平行排列存在。结合衍射数据和能量计算，对分子堆积结构进行了详细研究。角链和中心链相对于a轴的取向角分别为±40°。利用电子和XRD数据，将最佳分子堆积模型分别精修至R因子为0.168和0.196。还对链堆积结构与相关聚合物结构进行了简要比较。
