TY - JOUR
T1 - Crystalline mono- and multilayer self-assemblies of oligothiophenes at the air-water interface
AU - Isz, Sandrine
AU - Weissbuch, Isabelle
AU - Kjaer, Kristian
AU - Bouwman, Wim G.
AU - Als-Nielsen, Jens
AU - Palacin, Serge
AU - Ruaudel-Teixier, Annie
AU - Leiserowitz, Leslie
AU - Lahav, Meir
PY - 1997/1/1
Y1 - 1997/1/1
N2 - The formation of Langmuir monolayers at the air water interface has long been believed to be limited to amphiphilic molecules containing a hydrophobic chain and a hydrophilic headgroup. Here we report the formation of crystalline mono- and multilayer self-assemblies of oligothiophenes, a class of aromatic nonamphiphilic molecules, self-aggregated at the air water interface. As model systems we have examined the de position of quaterthiophene (S4), quinquethiophene (S5), and sexithiophene (S6) from chloroform solutions on tile water surface. The structures of the films were determined by surface pressure area isotherms, by scanning force microscopy (SFM after transfer of the films onto atomically smooth mica, by cryo-transmission electron microscopy (Cryo-TEM) on vitreous ice, and by grazing incidence synchrotron X-ray diffraction (GII) directly on the water surface. S4 forms two polymorphic crystalline multilayers. In polymorph χ, of structure very similar to that of the three-dimensional solid, the molecules are aligned with their long molecular axis tilted by about 23 from the normal to the water surface. In polymorph β the long molecular axis is perpendicular to the water surface. S5 self-aggregates at tile water surface to form mixtures of monolayers and bilayers of the β polymorph: S6, forms primarily crystalline monolayers of both χ and β forms. The crystalline assemblies preserve their integrity during transfer from the water surface onto solid supports. The relevance of the present results for the understanding of the early stages of crystal nucleation is presented.
AB - The formation of Langmuir monolayers at the air water interface has long been believed to be limited to amphiphilic molecules containing a hydrophobic chain and a hydrophilic headgroup. Here we report the formation of crystalline mono- and multilayer self-assemblies of oligothiophenes, a class of aromatic nonamphiphilic molecules, self-aggregated at the air water interface. As model systems we have examined the de position of quaterthiophene (S4), quinquethiophene (S5), and sexithiophene (S6) from chloroform solutions on tile water surface. The structures of the films were determined by surface pressure area isotherms, by scanning force microscopy (SFM after transfer of the films onto atomically smooth mica, by cryo-transmission electron microscopy (Cryo-TEM) on vitreous ice, and by grazing incidence synchrotron X-ray diffraction (GII) directly on the water surface. S4 forms two polymorphic crystalline multilayers. In polymorph χ, of structure very similar to that of the three-dimensional solid, the molecules are aligned with their long molecular axis tilted by about 23 from the normal to the water surface. In polymorph β the long molecular axis is perpendicular to the water surface. S5 self-aggregates at tile water surface to form mixtures of monolayers and bilayers of the β polymorph: S6, forms primarily crystalline monolayers of both χ and β forms. The crystalline assemblies preserve their integrity during transfer from the water surface onto solid supports. The relevance of the present results for the understanding of the early stages of crystal nucleation is presented.
KW - Cryo-transmission electron microscopy
KW - Monolayers
KW - Oligothiophenes
KW - Polymorphism
KW - Scanning force microscopy
UR - http://www.scopus.com/inward/record.url?scp=0030977617&partnerID=8YFLogxK
U2 - 10.1002/chem.19970030615
DO - 10.1002/chem.19970030615
M3 - Article
AN - SCOPUS:0030977617
SN - 0947-6539
VL - 3
SP - 930
EP - 939
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 6
ER -