Chemistry Reference
In-Depth Information
Figure 7.7 Schematic representation of the temperature-induced change in the MSP
composed of terpy end-capped ditopic monomers and Fe
II
dihexadecyl phosphate. The
temperature-induced transition results in a distortion of the metal ion coordination geometry,
which occurs because of the melting of the amphiphilic counterions, giving rise to a
reversible transition from a diamagnetic low spin state to a paramagnetic high spin state
(Bodenthin et al. 2005).
(Mebip) or terpy, then the different segments along the backbone of the MSP can
phase segregate. This phase segregation can result in physically cross-linked films,
which can exhibit thermoplastic elastomeric properties. Not all MSPs show this
type of phase segregation. For example, MSPs based on polymeric aromatic species
such as poly ( p-phenylene ethynylene)s (5; Knapton, Rowan, et al. 2006) or poly
( p-xylylene)s (6; Knapton, Iyer, et al. 2006) show very different behavior
(Fig. 7.8). The self-assembly formation of an MSP offers an attractive approach to
the assembly of high molecular weight conjugated macromolecules from well-
defined, easy to process precursors (El-Ghayoury et al. 2002; Chen and Lin 2007).
MSPs of 5
.
Fe(ClO
4
)
2
yielded soluble easy to process materials that formed mechani-
cally stable films and fibers with metal ions [e.g., r.t. modulus: Fe(ClO
4
)
2
80 MPa].
Wide-angle X-ray scattering data of these films is not consistent with the phase
segregation of the core and complex units, although a lamellae structure is observed
