Abstract
The kinetics of phase transitions in three-dimensional bulk materials are commonly presented in transformation diagrams. Time-temperature transformation (TTT) and continuous-cooling-transformation (CCT) diagrams plot the time required to transform specific fractions of the material to the new phase by cooling below a transition temperature. Transformation occurs isothermally for the TTT diagrams and during continuous cooling through a range of temperatures for CCT curves. Here we present analogous transformation diagrams for two-dimensional monolayers, which collapse at the equilibrium spreading pressure (π e) to form a three-dimensional bulk phase. Time-surface pressure-transformation (TπT) diagrams give the time required for specific fractions of the film to collapse when surface pressure is constant, and continuous-compression-transformation diagrams give the same information when surface pressure varies continuously. The diagrams, constructed here from previously reported data for 1-palmitoyl-2-oleoyl phosphatidylcholine, provide insights into the behavior of the films. The TπT diagrams successfully predict the existence and approximate magnitude of a threshold rate for compressing the films to high surface pressures above π e and the approximate shape of isotherms obtained with different rates of interfacial compression. The diagrams also caution that the behavior of mixed monolayers, explained previously in terms of compositional changes, can instead result from collapse that varies with surface pressure. Finally, the similarity between the shapes of the TTT and TπT diagrams, with the time for transformation passing through a minimum and then increasing as the systems deviate further from equilibrium, suggests that analogous mechanisms determine the behavior of both systems.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 10100-10106 |
| Number of pages | 7 |
| Journal | Langmuir |
| Volume | 20 |
| Issue number | 23 |
| DOIs | |
| State | Published - Nov 9 2004 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Colloid and Surface Chemistry
Cite this
Transformation diagrams for the collapse of a phospholipid monolayer. / Rugonyi, Sandra; Smith, Ethan C.; Hall, Stephen (Steve).
In: Langmuir, Vol. 20, No. 23, 09.11.2004, p. 10100-10106.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Transformation diagrams for the collapse of a phospholipid monolayer
AU - Rugonyi, Sandra
AU - Smith, Ethan C.
AU - Hall, Stephen (Steve)
PY - 2004/11/9
Y1 - 2004/11/9
N2 - The kinetics of phase transitions in three-dimensional bulk materials are commonly presented in transformation diagrams. Time-temperature transformation (TTT) and continuous-cooling-transformation (CCT) diagrams plot the time required to transform specific fractions of the material to the new phase by cooling below a transition temperature. Transformation occurs isothermally for the TTT diagrams and during continuous cooling through a range of temperatures for CCT curves. Here we present analogous transformation diagrams for two-dimensional monolayers, which collapse at the equilibrium spreading pressure (π e) to form a three-dimensional bulk phase. Time-surface pressure-transformation (TπT) diagrams give the time required for specific fractions of the film to collapse when surface pressure is constant, and continuous-compression-transformation diagrams give the same information when surface pressure varies continuously. The diagrams, constructed here from previously reported data for 1-palmitoyl-2-oleoyl phosphatidylcholine, provide insights into the behavior of the films. The TπT diagrams successfully predict the existence and approximate magnitude of a threshold rate for compressing the films to high surface pressures above π e and the approximate shape of isotherms obtained with different rates of interfacial compression. The diagrams also caution that the behavior of mixed monolayers, explained previously in terms of compositional changes, can instead result from collapse that varies with surface pressure. Finally, the similarity between the shapes of the TTT and TπT diagrams, with the time for transformation passing through a minimum and then increasing as the systems deviate further from equilibrium, suggests that analogous mechanisms determine the behavior of both systems.
AB - The kinetics of phase transitions in three-dimensional bulk materials are commonly presented in transformation diagrams. Time-temperature transformation (TTT) and continuous-cooling-transformation (CCT) diagrams plot the time required to transform specific fractions of the material to the new phase by cooling below a transition temperature. Transformation occurs isothermally for the TTT diagrams and during continuous cooling through a range of temperatures for CCT curves. Here we present analogous transformation diagrams for two-dimensional monolayers, which collapse at the equilibrium spreading pressure (π e) to form a three-dimensional bulk phase. Time-surface pressure-transformation (TπT) diagrams give the time required for specific fractions of the film to collapse when surface pressure is constant, and continuous-compression-transformation diagrams give the same information when surface pressure varies continuously. The diagrams, constructed here from previously reported data for 1-palmitoyl-2-oleoyl phosphatidylcholine, provide insights into the behavior of the films. The TπT diagrams successfully predict the existence and approximate magnitude of a threshold rate for compressing the films to high surface pressures above π e and the approximate shape of isotherms obtained with different rates of interfacial compression. The diagrams also caution that the behavior of mixed monolayers, explained previously in terms of compositional changes, can instead result from collapse that varies with surface pressure. Finally, the similarity between the shapes of the TTT and TπT diagrams, with the time for transformation passing through a minimum and then increasing as the systems deviate further from equilibrium, suggests that analogous mechanisms determine the behavior of both systems.
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UR - http://www.scopus.com/inward/citedby.url?scp=9144220950&partnerID=8YFLogxK
U2 - 10.1021/la049081t
DO - 10.1021/la049081t
M3 - Article
C2 - 15518500
AN - SCOPUS:9144220950
VL - 20
SP - 10100
EP - 10106
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 23
ER -