Department of Chemical Engineering, Shiv Nadar University, Gautam Buddha Nagar, 201314, India.
J Mol Model. 2022 Mar 5;28(4):83. doi: 10.1007/s00894-022-05069-z.
Density functional theory and molecular dynamic simulations were used to understand the microscopic-level interactions of pectin-based thin films with moisture (HO), carbon dioxide (CO), and oxygen (O). Galacturonic acid (GA), which forms ~65% of the smooth region of pectin polymer, was chosen for the current study. The electrostatic potential and Fukui function maps indicate that oxygen atoms of -OH groups of GA are the most reactive sites for electrophilic attack and hydrogen atoms on the carboxylic group (-COOH) are the reactive sites for nucleophilic attack. The GA molecule has shown strong interaction via hydrogen bonding with HO (E= ~ 40 kJ/mol) followed by CO (E = ~ -13 kJ/mol). Nucleophilic O showed insignificant interaction with GA. Surface interaction, adsorption, and diffusion of sorbate molecules on the GA film followed the order of HO >CO > O. Molecular interaction studies provided atomistic insights into the weak moisture and high gas barrier properties of pectin films.
采用密度泛函理论和分子动力学模拟方法，研究了果胶基薄膜与水分（HO）、二氧化碳（CO）和氧气（O）的微观相互作用。在当前研究中，选择半乳糖醛酸（GA）作为果胶聚合物平滑区域的65%组成部分。静电势和 Fukui 函数图表明，GA 的-OH 基团中的氧原子是亲电攻击的最活泼位点，而羧酸基团（-COOH）上的氢原子是亲核攻击的活性位点。GA 分子通过氢键与 HO（E=40 kJ/mol）形成较强的相互作用，随后与 CO（E =~-13 kJ/mol）形成较强的相互作用。亲核性的 O 与 GA 的相互作用不明显。吸附质分子在 GA 膜上的表面相互作用、吸附和扩散遵循 HO > CO > O 的顺序。分子相互作用研究为果胶膜的弱吸湿性和高气体阻隔性能提供了原子水平的见解。
