Hammond Oliver S, Morris Daniel C, Bousrez Guillaume, Li Sichao, de Campo Liliana, Recsei Carl, Moir Michael, Glavatskih Sergei, Rutland Mark W, Mudring Anja-Verena
Department of Biological and Chemical Engineering and iNANO, Aarhus University, Aarhus C 8000, Denmark.
Department of Materials and Environmental Chemistry, Stockholm University, Stockholm 114 18, Sweden.
ACS Sustain Chem Eng. 2024 Jan 22;12(5):1816-1821. doi: 10.1021/acssuschemeng.3c04736. eCollection 2024 Feb 5.
Commercial (protiated) samples of the "green" and biodegradable bioester 2-ethylhexyl laurate (2-EHL) were mixed with D-2-EHL synthesized by hydrothermal deuteration, with the mixtures demonstrating bulk structuring in small-angle neutron scattering measurements. Analysis in a polymer scattering framework yielded a radius of gyration () of 6.5 Å and a Kuhn length (alternatively described as the persistence length or average segment length) of 11.2 Å. Samples of 2-EHL dispersed in acetonitrile formed self-assembled structures exceeding the molecular dimensions of the 2-EHL, with a mean aggregation number () of 3.5 ± 0.2 molecules across the tested concentrations. We therefore present structural evidence that this ester can function as a nonionic (co)surfactant. The available surfactant-like conformations appear to enable performance beyond the low calculated hydrophilic-lipophilic balance value of 2.9. Overall, our data offer an explanation for 2-EHL's interfacial adsorption properties via self-assembly, resulting in strong emolliency and lubricity for this sustainable ester-based bio-oil.
将市售（质子化）的“绿色”可生物降解生物酯月桂酸2-乙基己酯（2-EHL）与通过水热氘化合成的D-2-EHL混合，在小角中子散射测量中，混合物呈现出整体结构。在聚合物散射框架下的分析得出回转半径（）为6.5 Å，库恩长度（也称为持久长度或平均链段长度）为11.2 Å。分散在乙腈中的2-EHL样品形成了超过2-EHL分子尺寸的自组装结构，在所测试的浓度范围内，平均聚集数（）为3.5±0.2个分子。因此，我们提供了结构证据，证明这种酯可以作为非离子（共）表面活性剂发挥作用。现有的类似表面活性剂的构象似乎能够实现超出计算得出的低亲水亲油平衡值2.9的性能。总体而言，我们的数据通过自组装解释了2-EHL的界面吸附特性，从而使这种可持续的酯基生物油具有很强的润肤性和润滑性。
