Hh. Song et al., Poly(2,5-dihydroxy-1,4-phenylene benzobisthiazole)/poly(1,4-phenylene benzobisthiazole) copolymers: Chain packing and properties, J POL SC PP, 39(5), 2001, pp. 559-565
Crystal-packing, optical, and electrical properties of poly(2,5-dihydroxy-1
,4-phenylene benzobisthiazole) (DiOH-PBZT) and copolymers of DiOH-PBZT/poly
(1,4-phenylene-benzobisthiazole) (PBZT) were examined. Intramolecular hydro
gen bonds between the hydroxyl units and the neighboring nitrogen atoms, as
evidenced by the IR spectra, led to the formation of a pseudoladder chain
structure and changed the chain packing. The (200) and (010) planes were bo
th affected by the copolymer composition, with the (200) plane spacing incr
easing from 5.895 to 6.482 Angstrom and the (010) plane spacing decreasing
from 3.539 to 3.404 Angstrom with the transition from the unsubstituted PBZ
T homopolymer to the DiOH-PBZT homopolymer. The cell dimensions of the copo
lymers were simple averages of those of the individual homopolymers, sugges
ting the isomorphic crystal structure formation of the two units. The c-axi
s spacing, how ever, remained unchanged. The increase in the conjugation le
ngth of the copolymers as the dihydroxy content increased was confirmed by
the bathochromic shift of the absorption band in the ultraviolet-visible sp
ectra. The intrinsic conductivities of the copolymers were 3 orders of magn
itude higher than that of the unsubstituted PBZT. (C) 2001 John Wiley & Son
s, Inc.