Hydrogen-bonded silica gels dispersed in a smectic liquid crystal: a random field XY system.
The effect on the nematic to smectic-A transition in octylcyanobiphenyl (8CB) due to dispersions of hydrogen-bonded silica (aerosil) particles is characterized with high-resolution x-ray scattering. The particles form weak gels in 8CB creating a quenched disorder that replaces the transition with the growth of short-range smectic correlations. The correlations include thermal critical fluctuations that dominate at high temperatures and a second contribution that quantitatively matches the static fluctuations of a random field system and becomes important at low temperatures.
Park
S
S
Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Leheny
R L
RL
Birgeneau
R J
RJ
Gallani
J-L
JL
Garland
C W
CW
Iannacchione
G S
GS