la5b04504_si_001.pdf (1.7 MB)
Tube-graft-Sheet Nano-Objects Created by A Stepwise Self-Assembly of Polymer-Polyoxometalate Hybrids
journal contribution
posted on 2016-01-19, 00:00 authored by Jing Tang, Xue-Ying Li, Han Wu, Li-Jun Ren, Yu-Qi Zhang, Hai-Xia Yao, Min-Biao Hu, Wei WangIn this work, we report the preparation
of complex nano-objects
by means of a stepwise self-assembly of two polymer-polyoxometalate
hybrids (PPHs) in solution. The PPHs are designed and synthesized
by tethering two linear poly(ε-caprolactone)s (PCL) of different
molecular weights (MW) on a complex of a Wells-Dawson-type polyoxometalate
(POM) cluster and its countraions. The higher MW PCL–POM self-assembled
into nanosheets, while the lower MW PCL–POM assembled into
nanotubes just by altering the ratio of water in the DMF–water
mixed solvent system. The two nano-objects have a similar membrane
structure in which a PCL layer is sandwiched by the two POM-based
complex layers. The PCL layer in the nanosheets is semicrystalline,
while the PCL layer in the nanotubes is amorphous. We further exploited
this MW-dependence to self-assemble the nanotubes on the nanosheet
edges to create complex tube-graft-sheet nano-objects.
We found that the nanotubes nucleate on the four {110} faces of the
PCL crystal and then further grow along the crystallographic b-axis of the PCL crystal. Our findings offer hope for the
further development of nano-objects with increasing complexity.