title: Nanoscopic confinement through self-assembly: crystallization within micellar cores exhibits simple Gibbs-Thomson behavior.
abstract: It is well known that liquids confined to small nanoscopic pores and droplets exhibit thermal behavior very different from bulk samples. Less is known about liquids spontaneously confined through self-assembly into micellar structures. Here we demonstrate, using a very well-defined n-alkyl-poly(ethylene oxide) polymer system with a tunable structure, that n-alkane(s) forming 2-3 nm small micellar cores are affected considerably by confinement in the form of melting point depressions. Moreover, comparing the reduction in melting points, ΔT_{m}, determined through volumetric and calorimetric methods with the micellar core radius, R_{c}, obtained from small-angle x-ray scattering, we find excellent agreement with the well-known Gibbs-Thomson equation, ΔT_{m}∼R_{c}^{-1}. This demonstrates that the reduced size, i.e., the Laplace pressure, is the dominant parameter governing the melting point depression in micellar systems.
authors.affiliation: Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway.
authors.forename: Thomas
authors.initials: T
authors.lastname: Zinn
authors.affiliation: Jülich Centre for Neutron Science (JCNS) and Institute for Complex Systems (ICS),Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Willner
authors.affiliation: Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway.
authors.forename: Reidar
authors.initials: R
authors.lastname: Lund