influence of BCP morphology on the LC behavior in a system of poly[styrene-block2-((3-cholesteryloxycarbonyl)oxy)ethyl methacrylate] (PS-b-PChEMA) with varying f
PS (0.11–0.78) (Fischer et al. 1994). In samples with f
PS 0.78 and 0.11, they
observed S of PChEMA and PS, respectively whereas L and C of PS were predominant at other f. Only in samples with PChEMA spheres, the LC phase was N, and in
all other morphologies, SmA LC phase was observed. The Sm layer normal is
perpendicular to the BCP layer normal in the L forming samples and to the PS C
axis in the C forming samples. However, they did not observe PChEMA C. The
authors constructed a phase diagram that consisted of L, C (PChEMA matrix), PS S,
and PChEMA S. This phase behavior is independent of the type of the coil block and
similar phase structures were observed in system where poly n-butyl methacrylate
was used as the coil block.
0
4.1
4.3
4.5
4.7
4.9
0.2
20
32
43
41
51
40
Lamellae
Lamellae
with HPL
defects
37 wt%
59
49
57
63
56
58
79
50
54
24
12 wt%
Lamellae
Predominately
Lamellae
Cylinders
Layered Morphologies
Layered Morphologies
0.4
0.6
Liquid Crystal Volume Fraction, f
Log (M
n )
4.1
4.3
4.5
4.7
4.9
Log (M
n )
0.8
1
0
0.2
0.4
0.6
Liquid Crystal Volume Fraction, f
0.8
1
a
b
Fig. 16 Experimental phase diagram of PS-b-PMMA based side chain liquid crystalline block
copolymer with chiral biphenyl benzoate mesogen with (a) six and (b) ten carbon spacers
(Anthamatten et al. 1999)
7 Structure and Assembly of Liquid Crystalline Block Copolymers
201