Anharmonic magnetic deformation of self-assembled molecular nanocapsules.
High magnetic fields were used to deform spherical nanocapsules, self-assembled from bolaamphiphilic sexithiophene molecules. At low fields the deformation--measured through linear birefringence-scales quadratically with the capsule radius and with the magnetic field strength. These data confirm a long standing theoretical prediction [W. Helfrich, Phys. Lett. A 43, 409 (1973)10.1016/0375-9601(73)90396-4], and permit the determination of the bending rigidity of the capsules as (2.6+/-0.8) x 10(-21) J. At high fields, an enhanced rigidity is found which cannot be explained within the Helfrich model. We propose a complete form of the free energy functional that accounts for this behavior, and allows discussion of the formation and stability of nanocapsules in solution.
Manyuhina
O V
OV
Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
Shklyarevskiy
I O
IO
Jonkheijm
P
P
Christianen
P C M
PC
Fasolino
A
A
Katsnelson
M I
MI
Schenning
A P H J
AP
Meijer
E W
EW
Henze
O
O
Kilbinger
A F M
AF
Feast
W J
WJ
Maan
J C
JC