observed for many disubstituted organopolyphosphazenes, as listed in Chart 2. It is
also suggested that poly(dimethylphosphazene) (Kojima and Magill 1992) and poly
(diphenylphosphazene) (Cypryk et al. 1992; Kojima et al. 1994) exhibit a not wellidentified mesophase.
Similar to PDmSiO, a mesophase can only be observed in a poly(di-n-alkoxyphosphazene) with a limited range of n-alkyl chain length (3–5 carbon atoms) (Tur et al.
1991; Papkov et al. 1992). The nature of the mesophase was not fully identified since
the X-ray diffraction pattern features only one sharp peak in the small-angle region.
However, since the d-spacing of the sharp peak increases with the length of n-alkyl
chains and is consistently about 0.14 nm greater than the corresponding d-spacing in
the Col h phase of the highly structurally related PDmSiO, the mesophase is most
likely also a Col h phase.
A couple of poly[bis(1H, 1H-perfluoroalkoxy)phosphazenes] (Antipov et al.
1992) show a Col h phase. Among them, poly[bis(trifluoroethyl)phosphazene] has
been studied most extensively. The Col h phase of this polymer appears between
66
C and the isotropization temperature ~ 245
C (Allen et al. 1970; Kojima
and Magill 1984, 1985, 1989). Solid-state NMR results showed that polymer
backbone becomes highly mobile at the crystal-Col h transition. The side-chains are
somewhat mobile even in the crystalline phase (Young and Magill 1989).
An array of poly[bis(phenoxy)phosphazenes], including the unsubstituted parent
polymer and either meta- or para-substituted fluoro, chloro, bromo, and methyl
50
40
30
T (°C)
20
10
0
0
1
2
α → μ
β → μ
μ → i
3
10 5 /M n (mol/g)
M n = 27 900
4
5
6
Fig. 2 MW-dependent
transition temperatures of
PD2SiO, μ = Col h . (Reprinted
with permission from
Molenberg and Möller 1997.
Copyright (1997) American
Chemical Society)
P N
R
R
n
R =
O(CH 2 ) x H
OCH 2 (CF 2 ) y F
O
X
x = 3, 4, 5
y = 1, 2, 3
(either meta or para) F, Cl, Br, CH 3
(para) CH 3 O, CH 3 S, CH 3 CH 2 ,PhCH 2
X = H
Chart 2 Columnar phase-forming disubstituted organopolyphosphazenes
5 Columnar Phase-Forming Polymers
123
also suggested that poly(dimethylphosphazene) (Kojima and Magill 1992) and poly
(diphenylphosphazene) (Cypryk et al. 1992; Kojima et al. 1994) exhibit a not wellidentified mesophase.
Similar to PDmSiO, a mesophase can only be observed in a poly(di-n-alkoxyphosphazene) with a limited range of n-alkyl chain length (3–5 carbon atoms) (Tur et al.
1991; Papkov et al. 1992). The nature of the mesophase was not fully identified since
the X-ray diffraction pattern features only one sharp peak in the small-angle region.
However, since the d-spacing of the sharp peak increases with the length of n-alkyl
chains and is consistently about 0.14 nm greater than the corresponding d-spacing in
the Col h phase of the highly structurally related PDmSiO, the mesophase is most
likely also a Col h phase.
A couple of poly[bis(1H, 1H-perfluoroalkoxy)phosphazenes] (Antipov et al.
1992) show a Col h phase. Among them, poly[bis(trifluoroethyl)phosphazene] has
been studied most extensively. The Col h phase of this polymer appears between
66
C and the isotropization temperature ~ 245
C (Allen et al. 1970; Kojima
and Magill 1984, 1985, 1989). Solid-state NMR results showed that polymer
backbone becomes highly mobile at the crystal-Col h transition. The side-chains are
somewhat mobile even in the crystalline phase (Young and Magill 1989).
An array of poly[bis(phenoxy)phosphazenes], including the unsubstituted parent
polymer and either meta- or para-substituted fluoro, chloro, bromo, and methyl
50
40
30
T (°C)
20
10
0
0
1
2
α → μ
β → μ
μ → i
3
10 5 /M n (mol/g)
M n = 27 900
4
5
6
Fig. 2 MW-dependent
transition temperatures of
PD2SiO, μ = Col h . (Reprinted
with permission from
Molenberg and Möller 1997.
Copyright (1997) American
Chemical Society)
P N
R
R
n
R =
O(CH 2 ) x H
OCH 2 (CF 2 ) y F
O
X
x = 3, 4, 5
y = 1, 2, 3
(either meta or para) F, Cl, Br, CH 3
(para) CH 3 O, CH 3 S, CH 3 CH 2 ,PhCH 2
X = H
Chart 2 Columnar phase-forming disubstituted organopolyphosphazenes
5 Columnar Phase-Forming Polymers
123