mz6b00529_si_001.pdf (1.25 MB)
Enhancing Mechanochemical Activation in the Bulk State by Designing Polymer Architectures
journal contribution
posted on 2016-09-20, 13:49 authored by Hironori Oka, Keiichi Imato, Tomoya Sato, Tomoyuki Ohishi, Raita Goseki, Hideyuki OtsukaMechanoresponsive
polymers can have attractive functions; however,
the relationship between polymer architecture and mechanoresponsiveness
in the bulk state is still poorly understood. Here, we designed well-defined
linear and star polymers with a mechanophore at the center of each
architecture, and investigated the effect of molecular weight and
branched structures on mechanoresponsiveness in the solid state. Diarylbibenzofuranone,
which can undergo homolytic cleavage of the central C–C bond
by mechanical force to form blue-colored radicals, was used as a mechanophore
because the cleaved radicals could be evaluated quantitatively using
electron paramagnetic resonance measurements. We confirmed that longer
polymer chains induce mechanochemical activation more effectively
and found that, in the bulk state, the star polymers have higher sensitivity
to mechanical stress compared with a linear polymer having similar
molecular weight arm segment.