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Existence of Two‐Dimensional Physical Gels even at Zero Surface Pressure at the Air/Water Interface: Rheology of Self‐Assembled Domains of Small Molecules
Author(s) -
Veschgini Mariam,
Habe Taichi,
Mielke Salomé,
Inoue Shigeto,
Liu Xianhe,
Krafft Marie Pierre,
Tanaka Motomu
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201707009
Subject(s) - monolayer , viscoelasticity , mesoscopic physics , rheology , fluorocarbon , materials science , surface pressure , copolymer , hydrocarbon , langmuir , surface tension , self assembly , chemical physics , chemical engineering , polymer , polymer chemistry , adsorption , nanotechnology , composite material , chemistry , thermodynamics , organic chemistry , mechanics , physics , quantum mechanics , engineering
Films of mesoscopic domains self‐assembled from fluorocarbon/hydrocarbon diblock copolymers ( FnHm ) at the air/water interface were found to display highly elastic behavior. We determined the interfacial viscoelasticity of domain‐patterned FnHm Langmuir monolayers by applying periodic shear stresses. Remarkably, we found the formation of two‐dimensional gels even at zero surface pressure. These monolayers are predominantly elastic, which is unprecedented for surfactants, exhibiting gelation only at high surface pressures. Systematic variation of the hydrocarbon ( n =8; m =14, 16, 18, 20) and fluorocarbon ( n =8, 10, 12; m =16) block lengths demonstrated that subtle changes in the block length ratio significantly alter the mechanics of two‐dimensional gels across one order of magnitude. These findings open perspectives for the fabrication of two‐dimensional gels with tuneable viscoelasticity via self‐assembly of mesoscale, low‐molecular‐weight materials.