Complex Crystal Formation of Poly(L-lactide) with Solvent Molecules
Complex Crystal Formation of Poly(L-lactide) with Solvent Molecules
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DOI：
10.1021/ma202324g
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发表时间：
2012-02-14
期刊：
影响因子：
5.5
通讯作者：
Sumita, Masao
中科院分区：
文献类型：
--
作者：
Marubayashi, Hironori;Asai, Shigeo;Sumita, Masao
通过对多种有机溶剂的筛选实验，发现聚L-乳酸（PLLA）在室温以下与特定的有机溶剂如四氢呋喃（THF）和N，N-二甲基甲酰胺（DMF）形成结晶复合物（ε型）。结果表明，PLLA对低分子量化合物具有较高的选择性形成电子晶体。通过对ε-型的纤维图分析，发现PLLA链呈10（7）（左手10（3））螺旋构象，并堆积在正交晶格中（a = 1.5-1.6 nm，B = 1.2-1.3 nm，c = 2.8-2.9 nm，α = β = γ = 90度）。基于R因子和堆积能的计算，提出了PLLA-DMF复合物的合理晶体结构，其中四个PLLA链和八个客体溶剂堆积在晶胞中。
By screening examinations for a wide variety of organic solvents, we found that poly(L-lactide)(PLLA) forms the crystalline complex (epsilon-form) with the specific organic solvents such as tetrahydrofuran (THF) and N,N-dimethylformamide (DMF) below room temperature. It was revealed that PLLA has high selectivity for low molecular weight compounds to form the e-crystals. By fiber diagram analyses for the epsilon-forms, it was found that PLLA chains take the 10(7) (left-handed 10(3)) helical conformation and are packed in the orthorhombic lattice (a = 1.5-1.6 nm, b = 1.2-1.3 nm, c = 2.8-2.9 nm, and alpha = beta = gamma = 90 degrees). Based on R-factor and packing energy calculations, the plausible crystal structure of PLLA-DMF complex was proposed, in which four PLLA chains and eight guest solvents are packed m the-unit cell.