Growth of lamellar crystals of poly(γ-benzyl-l-glutamate)
Growth of lamellar crystals of poly(γ-benzyl-l-glutamate)
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DOI：
10.1016/0032-3861(75)90099-3
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发表时间：
1975
期刊：
影响因子：
4.6
通讯作者：
C. Price;P. Harris;T. J. Holton;R. B. Stubbersfield
中科院分区：
文献类型：
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作者：
C. Price;P. Harris;T. J. Holton;R. B. Stubbersfield
Padden和Keith证明，在适当选择的条件下，聚甘氨酸、聚l -酪氨酸，可能还有聚t-丙氨酸，都可以在溶液中结晶，形成分子链折叠的单晶。发现片层晶体表现出许多通常与传统合成聚合物单晶相关的形态特征2。然而，对于聚l -酪氨酸和聚l -丙氨酸，即使在结晶状态下，溶剂也与聚合物络合；溶剂的蒸发导致结晶秩序的丧失。同一学派后来进行的研究包括从水溶液中生长聚l -谷氨酸3的碱土盐的单晶和由二价阴离子稳定的聚l -赖氨酸4的晶体。本文报道了一种生长聚（7-苄基- l-谷氨酸）（PBLG）片层晶体的方法。由于其在多种溶剂中的溶解性，PBLG已被许多工作者用作研究纤维蛋白行为的有用模型化合物。对该聚合物进行了大量稀溶液研究6-8。结晶研究表明，PBLG能够从溶液中以纤维聚集体的形式结晶：根据溶剂和沉淀条件，这些聚集体可能是单链、绳索、棒状或环形。此外，通过x射线和电子衍射分析了聚合物的晶体结构，并对拉伸溶液浇铸薄膜h进行了研究。尽管在亚三甲苯溶液中的碱卤化物上外延生长了PBLG片层单晶，但以前没有报道过直接生长PBLG片层单晶的方法。在Carr等人进行的后一项工作中，12个电子衍射和显微镜研究表明，片层含有链折叠的a-螺旋主链骨架，但庞大的侧基仍然无序。
It was shown by Padden and Keith that under suitably chosen conditions polyglycine, poly (L-tyrosine), and probably poly (t-alanine) as well, could crystallize from solution to form single crystals with folded molecular chains. The lamellar crystals were found to exhibit many of the morphological features normally associated with single crystals of more conventional synthetic polymers 2. With poly (L-tyrosine) and poly (L-alanine) it appeared, however, that solvent was complexed with the polymer even in the crystalline state; evaporation of the solvent resulted in the loss of crystalline order. Later studies carried out by the same school included the growth of single crystals of alkaline earth salts of poly (L-glutamic acid) 3 from aqueous solution and crystals of poly (L-lysine) 4 stabilized by divalent anions.In this communication we report a method for growing lamellar crystals of poly (7-benzyl-L-glutamate)(PBLG). Because of its solubility in a wide variety of solvents, PBLG has been used by many workers as a useful model compound for investigating the behaviour of fibrous proteins s. Numerous dilute solution studies 6-8 have been carried out• on the polymer. Crystallization studies have shown that PBLG is able to crystallize from solution in the form of fibrillar aggregates: these maybe single strands, ropes, rods or toroids depending on the solvent and precipitation conditions 9. Also the crystalline structure of the polymer has been analysed by X-ray and electron diffraction studies carried out on stretched solution cast films' H. No direct method of growing lamellar single crystals of PBLG has been reported previously although they have been grown epitaxially on alkali halides from mesitylene solution. In the latter work carried out by Carr et al. 12 electron diffraction and microscopy studies indicated that the lamellae contained chainfolded a-helical main-chain backbones, but that the bulky side groups remained disordered.