Structural transitions in polydiacetylene Langmuir films.
Polydiacetylene (PDA) Langmuir films (LFs) were investigated directly at the air/water interface using in situ synchrotron grazing incidence X-ray diffraction, and ex situ transmissison electron microscopy and diffraction. The films were compressed and polymerized on pure water. A crystallographic model describes the structures and phase transitions of the unpolymerized (monomer) film, via the metastable (blue phase), to the fully stable PDA red phase as a function of irradiation dose. The monomer-to-blue-to-red chromatic phase transitions are accompanied by changes in the in-plane crystal structure and pendant chains packing arrangement from arced alkyl chains (in the monomer and blue phases) to near-vertical closely packed chains in the red phase. Notably, the characteristic linear strand morphology of PDA films can be explained as a direct result of the marked decrease in spacing between adjacent polymer chains upon transition from the blue to the red phase.
Lifshitz
Yevgeniy
Y
Department of Materials Engineering, Ilse Katz Institute of Nanoscience and Nanotechnology, Beer-Sheva, Israel.
Golan
Yuval
Y
Konovalov
Oleg
O
Berman
Amir
A
D000388:Air; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods; D008055:Lipids / Q000737:chemistry; D008567:Membranes, Artificial; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008956:Models, Chemical; D015394:Molecular Structure; D000078789:Polyacetylene Polymer; D011108:Polymers / Q000737:chemistry*; D053279:Polyynes / Q000737:chemistry*; D012997:Solvents; D013499:Surface Properties; D017356:Synchrotrons; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
D008055:Lipids; D008567:Membranes, Artificial; D000078789:Polyacetylene Polymer; D011108:Polymers; D012997:Solvents; D014867:Water; D053279:Polyynes; C082361:polydiacetylene