A Reversibly Switching Surface

• Published in: Science (American Association for the Advancement of Science) Vol. 299; no. 5605; pp. 371 - 374
• Main Authors: Lahann, Joerg, Mitragotri, Samir, Tran, Thanh-Nga, Kaido, Hiroki, Sundaram, Jagannathan, Choi, Insung S., Hoffer, Saskia, Somorjai, Gabor A., Langer, Robert
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 17.01.2003; The American Association for the Advancement of Science
• Subjects: Adsorption; Chemical Phenomena; Chemistry, Physical; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Design; Electrical potential; Electricity; Electrochemistry; Electrodes; Energy; Esters; Exact sciences and technology; Gold; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Infrared radiation; Inhalants; Materials research; Materials science; Molecular chains; Molecular Conformation; Molecular interactions; Molecular Structure; Molecules; Nanoscale materials and structures: fabrication and characterization; Palmitic Acids - chemistry; Physics; Solid-fluid interfaces; Solvents; Spectroscopy; Spectrum Analysis; Surface Properties; Surface tension; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermodynamics; Wettability; Wetting; Wetting (Surface chemistry); Dynamic response; Gold; Electric potential; Reversible processes; Thiols; Long chain; Theoretical study; Surfaces; Sum frequency; Carboxylic acids; Contact angle; Experimental study; Fatty acids; Conformational changes; Switching; Interface properties; Self-assembly; Wettability; Transition elements; Saturated aliphatic compound; Monolayers; Surface properties; Organic compounds
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1078933

We report the design of surfaces that exhibit dynamic changes in interfacial properties, such as wettability, in response to an electrical potential. The change in wetting behavior was caused by surface-confined, single-layered molecules undergoing conformational transitions between a hydrophilic and a moderately hydrophobic state. Reversible conformational transitions were confirmed at a molecular level with the use of sum-frequency generation spectroscopy and at a macroscopic level with the use of contact angle measurements. This type of surface design enables amplification of molecular-level conformational transitions to macroscopic changes in surface properties without altering the chemical identity of the surface. Such reversibly switching surfaces may open previously unknown opportunities in interfacial engineering.