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Self‐Organization of Poly(ethylene oxide) on the Surface of Aqueous Salt Solutions
Author(s) -
Fuchs Christian,
Hussain Hazrat,
Amado Elkin,
Busse Karsten,
Kressler Joerg
Publication year - 2015
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201400451
Subject(s) - aqueous solution , ethylene oxide , poly ethylene , salt (chemistry) , oxide , polymer chemistry , materials science , ethylene , chemical engineering , polymer science , chemistry , polymer , organic chemistry , copolymer , composite material , catalysis , engineering
It is demonstrated that stable Langmuir films of poly(ethylene oxide) (PEO) can be formed up to surface pressures of 30 mN m −1 when potassium carbonate K 2 CO 3 is added to the aqueous subphase. Generally, PEO homopolymer cannot stay on the water surface at a surface pressure ≥10 mN m −1 due to its high water solubility. To prepare stable monolayer films, PEO can be modified with hydrophobic moieties. However, by exploiting the salting out effect by adding certain salts (K 2 CO 3 or MgSO 4 ) into the aqueous subphase, not only very stable films but also unusual self‐organization can be achieved by the PEO homopolymer on the surface of the aqueous solution. Thus, a series of OH‐terminated PEOs is found to form a stable monolayer at K 2 CO 3 concentrations of 2 M and above in the aqueous subphase, and the stability of the film increases with an increase in K 2 CO 3 concentration. Hysteresis experiments are also carried out. During the phase transition induced by progressive compression, self‐organization into well‐defined domains with sizes in the micrometer range are observed, and with further compression and holding of the film for 30 min and above the microdomains transform into a crystalline morphology as visualized by Brewster angle microscopy.