Emergence of Supramolecular Order from Combined Linear Amphiphilic and Diphosphonate Molecules

Self-assembled molecules exhibit key functionalities for the development of novel technologies and applications. Usually, molecular systems that exhibit long-range positional order are employed in their pure form. In this work, we observe that a combination of an amphiphilic molecule, tetradecyl-phosphonic acid (TPA), and a diphosphonate molecule with a similar length, 1,10-decyldiphosphonic acid (DdPA), induces distinct long-range ordered structures depending on the relative volume of dilutions used for drop coating. Starting from 0.2 mM diluted ethanol solutions of each molecule and combining both in distinct proportions that range from 1:20 to 20:1, we were able to identify periodic molecular structures that consist of three and five molecules of TPA and DdPA arranged in symmetries and were retrieved by synchrotron X-ray diffraction. The possibility of deterministically building up such structures can be further developed to induce surface and bulk behaviors that better suit applications such as coatings for chemical and biological studies, as well as to engineer layers used in organic electronic applications.