All-atom molecular simulation study of cellulose acetate: amorphous structure and the dissolution of small molecule
All-atom molecular simulation study of cellulose acetate: amorphous structure and the dissolution of small molecule
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DOI：
10.1007/s10570-022-04616-4
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发表时间：
2022-05
期刊：
影响因子：
5.7
通讯作者：
Ryota Matsuba;Hiroyuki Kubota;N. Matubayasi
中科院分区：
文献类型：
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作者：
Ryota Matsuba;Hiroyuki Kubota;N. Matubayasi
采用分子动力学模拟方法对醋酸纤维素（CA）进行了全原子分析。分子间的相互作用，阐明了在无定形状态下与乙酰基取代度（DS）的2，2.5，和3，和溶解的能量处理为H2O，CO2，和CH4。据观察，CA的无定形，DS强烈影响CA的羟基之间的氢键和吡喃糖环的短程包装变得更紧密的乙酰化。用溶剂化的能量表示法计算了溶解自由能。溶解到CA中的顺序为H2O > CO2> CH4，并且溶解自由能的DS依赖性仅对于DS = 2和2.5之间的H2O明显。进一步讨论了分子间相互作用组分的作用。有人认为，静电分量带来的DS依赖的溶解自由能为H2O以及在CO2和CH4之间的CA的亲和力的差异。货车德瓦耳斯组分仍然是占主导地位的非极性CO2和CH4，和它的总贡献从乙酰基和CA的主链基团是弱依赖于DS。并讨论了溶解能学与结构的关系。图形摘要
All-atom analysis was conducted for cellulose acetate (CA) using molecular dynamics simulation. The intermolecular interactions were elucidated at the amorphous state with degrees of acetyl substitution (DS) of 2, 2.5, and 3, and the energetics of dissolution was treated for H2O, CO2, and CH4. It was observed for the CA amorphous that DS strongly affects the hydrogen bonding among the hydroxy groups of CA and that the short-range packing of pyranose rings becomes tighter with acetylation. The free energy of dissolution was computed by the energy-representation method of solvation. The dissolution into CA was more favorable in the order of H2O > CO2> CH4, and the DS dependence of the dissolution free energy was evident only for H2O between DS = 2 and 2.5. The roles of the intermolecular interaction components were further addressed. It was seen that the electrostatic component brings the DS dependence of the dissolution free energy for H2O as well as the difference in the affinity to CA between CO2and CH4. The van der Waals component was still dominant for the nonpolar CO2and CH4, and the summed contribution to it from the acetyl and main-chain groups of CA was weakly dependent on DS. The connection of the dissolution energetics with the underlying structures is also discussed.Graphical abstract