{"title":"Steric effects stabilize reverse micelle domains in supercritical CO2 by determined conformation: restrictions of water and cations†","authors":"Huiwen Sun, Meng Wang, Pan Wang and Muhan Wang","doi":"10.1039/D3ME00115F","DOIUrl":null,"url":null,"abstract":"<p >Previous research into designing CO<small><sub>2</sub></small>-philic surfactants has certain limitations, necessitating the exploration of effective design concepts for hydrocarbon surfactants, which are far less expensive and less toxic than fluorocarbon surfactants. In this study, molecular simulations were employed to extensively investigate preassembled models of four representative surfactants and elucidate the structure of water-in-carbon dioxide (W/C) microemulsions. Innovative strategies for evaluating the stability of surfactant microemulsions and designing CO<small><sub>2</sub></small>-philic surfactants were developed. Thorough investigations into the microemulsion structure revealed that fluorocarbon surfactants formed stable micelles due to the steric effect arising from the determined conformation, which is restricted by hydrogen bonds. Fluorination at the terminal end of the surfactant tail will lead to a more restrictive structure, acting as a steric hindrance. Investigation into a hydrocarbon surfactant also determined that the group at the surfactant tail terminal formed hydrogen bonds with water molecules, restricting the conformation of the surfactant. This is a feasible method <em>via</em> fluorine substitution. This work reveals that steric effects arising from water molecules and cation restrictions can guide surfactant synthesis strategies or stabilize reverse micelles in scCO<small><sub>2</sub></small> systems. With the development of these basic design principles, the synthesis of efficient hydrocarbon surfactants will be achieved in the foreseeable future.</p>","PeriodicalId":91,"journal":{"name":"Molecular Systems Design & Engineering","volume":null,"pages":null},"PeriodicalIF":3.2000,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Molecular Systems Design & Engineering","FirstCategoryId":"5","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2024/me/d3me00115f","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Previous research into designing CO2-philic surfactants has certain limitations, necessitating the exploration of effective design concepts for hydrocarbon surfactants, which are far less expensive and less toxic than fluorocarbon surfactants. In this study, molecular simulations were employed to extensively investigate preassembled models of four representative surfactants and elucidate the structure of water-in-carbon dioxide (W/C) microemulsions. Innovative strategies for evaluating the stability of surfactant microemulsions and designing CO2-philic surfactants were developed. Thorough investigations into the microemulsion structure revealed that fluorocarbon surfactants formed stable micelles due to the steric effect arising from the determined conformation, which is restricted by hydrogen bonds. Fluorination at the terminal end of the surfactant tail will lead to a more restrictive structure, acting as a steric hindrance. Investigation into a hydrocarbon surfactant also determined that the group at the surfactant tail terminal formed hydrogen bonds with water molecules, restricting the conformation of the surfactant. This is a feasible method via fluorine substitution. This work reveals that steric effects arising from water molecules and cation restrictions can guide surfactant synthesis strategies or stabilize reverse micelles in scCO2 systems. With the development of these basic design principles, the synthesis of efficient hydrocarbon surfactants will be achieved in the foreseeable future.
期刊介绍:
Molecular Systems Design & Engineering provides a hub for cutting-edge research into how understanding of molecular properties, behaviour and interactions can be used to design and assemble better materials, systems, and processes to achieve specific functions. These may have applications of technological significance and help address global challenges.