the bulky coils, whereas keeping the f
coil constant and increasing the length of the
rods resulted in stabilization of mushrooms. Introducing a bulky dendritic wedge at
the end of the rods increased the steric hindrance of the packing of the mushrooms
and the morphology was completely altered resulting in ribbon-shaped structures of
width 10 nm and thickness 2 nm.
Lee et al. systematically varied the chemical structure of the rod and coil blocks
and reported very interesting phase behavior in a rod-coil oligomeric system where
the rod units are made of mesogens (Jin et al. 2004; Lee and Cho 2001; Lee et al.
2000, 2001, 2004; Lee and Yoo 2002). LC ordering was predominant in longer rods
(two biphenyl units) compared to smaller rods (single biphenyl unit) due to the
increased lateral interactions between the rods (keeping the coil segment constant)
and leading to the formation of L structures. The rod domains transform into
hexagonal columns as f
coil increased. This transformation can also be brought
O 2 N
CH 3 (CH 2 ) 3
CL
N
N
NCH 2 CH 2 OOC
COO
COO
OOC
n
OOC
OOC(CH 2 ) 7 COO
Et
[ [ [
[
CH 2 CH
n
m n+m=9
–
COO
OOC
OOC
OH
–
9
a
b
c
Fig. 7 Schematic representation of (a) stripes and (b) super-lattice aggregates of low M n mesogenic units. (c) Mushroom-shaped aggregates. (Adapted from Lee et al. 2001; Stupp et al. 1997)
188
K. K. Tenneti et al.
coil constant and increasing the length of the
rods resulted in stabilization of mushrooms. Introducing a bulky dendritic wedge at
the end of the rods increased the steric hindrance of the packing of the mushrooms
and the morphology was completely altered resulting in ribbon-shaped structures of
width 10 nm and thickness 2 nm.
Lee et al. systematically varied the chemical structure of the rod and coil blocks
and reported very interesting phase behavior in a rod-coil oligomeric system where
the rod units are made of mesogens (Jin et al. 2004; Lee and Cho 2001; Lee et al.
2000, 2001, 2004; Lee and Yoo 2002). LC ordering was predominant in longer rods
(two biphenyl units) compared to smaller rods (single biphenyl unit) due to the
increased lateral interactions between the rods (keeping the coil segment constant)
and leading to the formation of L structures. The rod domains transform into
hexagonal columns as f
coil increased. This transformation can also be brought
O 2 N
CH 3 (CH 2 ) 3
CL
N
N
NCH 2 CH 2 OOC
COO
COO
OOC
n
OOC
OOC(CH 2 ) 7 COO
Et
[ [ [
[
CH 2 CH
n
m n+m=9
–
COO
OOC
OOC
OH
–
9
a
b
c
Fig. 7 Schematic representation of (a) stripes and (b) super-lattice aggregates of low M n mesogenic units. (c) Mushroom-shaped aggregates. (Adapted from Lee et al. 2001; Stupp et al. 1997)
188
K. K. Tenneti et al.