Abstract
Monolayers of linear and star-shaped amphiphilic Poly(ethylene oxide)-b-Poly(e-caprolactone) copolymers (PEO-b-PCL) were studied at the air-water interface by surface pressure-mean mol. area (p-MMA) isotherms and compression-expansion hysteresis expts. The p-MMA isotherms of the linear copolymers exhibited three phase transitions at 6, 11 and 14mN/m, whereas only one transition at 14mN/m was obsd. for the star-shaped copolymers. The transition at 14mN/m arises from crystn. of the PCL segments and the transitions at 6 and 11mN/m are thought to arise from PEO dissoln. in the aq. subphase. The absence of the two PEO phase transitions for the star-shaped copolymers indicates a negligible surface activity of the star-shaped PEO core compared to the linear PEO analog. At. Force Microscopy imaging of the Langmuir-Blodgett films showed the presence of cryst. domains independent of the surface pressure, indicating that the Langmuir monolayers undergo morphol. changes (addnl. crystn.) during transfer to less hydrated solid surfaces. [on SciFinder (R)]
| Original language | English |
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| Title of host publication | Abstracts of Papers, 231st ACS National Meeting, Atlanta, GA, United States, March 26-30, 2006 |
| Pages | COLL-420 |
| Publication status | Published - 2006 |