物理化学学报2022，Vol.38Issue(12)：191-199,9.DOI:10.3866/PKU.WHXB202207006
液滴在超疏水植物叶面的沉积:实验和分子动力学模拟
Experimental and Molecular Dynamic Simulation of Droplet Deposition on Superhydrophobic Plant Leaf Surfaces
摘要
Abstract
Pesticide droplet deposition on targeted plant leaf surfaces is of great importance but remains a significant challenge,especially on leaf surfaces of superhydrophobic plants.The loss of sprayed pesticide droplets leads to the overuse of pesticides and environmental pollution.Therefore,in this study,we aimed at developing a system that was capable of enhancing droplet deposition on the surfaces of superhydrophobic plant leaves via hydrogen bonding between a bio-based surfactant and glycerol at low concentration(0.25％).The system based on the sorbitol-alkylamine surfactant(denoted as SSAS-C12)with a small amount of glycerol(0.001％)could efficiently inhibit droplet bouncing and splashing on different superhydrophobic/hydrophobic plant leaf surfaces.The results obtained indicated that the addition of glycerol did not change the surface tension,viscosity,contact angles on the plant leaf surfaces,and aggregate morphology of the SSAS-C12 solutions.Diffusion-ordered nuclear magnetic resonance spectroscopy revealed that glycerol accelerated the diffusion of SSAS-C12 molecules.More specifically,SSAS-C12 molecules could diffuse and adsorb on plant leaf surfaces within a short period of time.Other surfactants(denoted as DSSAS-C12 and BAPO-C12)with varying numbers of hydroxyl groups were used to verify the enhancement of the deposition on superhydrophobic plant leaf surfaces caused by hydrogen bonding.It was revealed that a decrease in the number of hydroxyl groups in the surfactant molecules led to a decrease in the number of hydrogen bonds between the glycerol and surfactant molecules.Moreover,the diffusion rates of the DSSAS-C12 and BAPO-C12 molecules in solution were low,causing the surfactant molecules to not reach the solid-liquid interface in time.Consequently,the droplets containing surfactant molecules(of DSSAS-C12 or BAPO-C12)bounced and broke up on the surfaces of plant leaves.Finally,we used molecular dynamics(MD)simulations to explore the energy and molecular distribution of different surfactant-glycerol mixtures.The energy evolution of the SSAS-C12-glycerol system and the distribution of surfactant molecules relative to the distance from the solid surface in the MD simulations showed that the addition of glycerol twisted the headgroup in SSAS-C12 via hydrogen bonding with glycerol.In this case,SSAS-C12 molecules experienced rapid diffusion and adsorption on the solid interface.Therefore,this study not only provided a constructive way to overcome the bouncing behavior of droplets but also prompted us to verify whether all hydrogen bonding interactions among different molecules could display similar control efficiencies through the rational selection of additives.关键词
动态沉积/生物表面活性剂/甘油/氢键/分子动力学模拟Key words
Impact dynamics/Bio-based surfactant/Glycerol/Hydrogen bond/Molecular dynamic simulation分类
化学化工引用本文复制引用
曹冲,张裴,曹立冬,刘铭鑫,宋玉莹,陈鹏,黄啟良,韩布兴..液滴在超疏水植物叶面的沉积:实验和分子动力学模拟[J].物理化学学报,2022,38(12):191-199,9.基金项目
The project was supported by the National Natural Science Foundation of China(32072469,22073104)and the Central Public-interest Scientific Institution Basal Research Fund(S2022XM16).国家自然科学基金(32072469,22073104)及中央级公益性科研院所基本科研业务费专项(S2022XM16)资助项目 （32072469,22073104）
