multistimuli responsive behaviors (Fig. 28) [50]. Firstly, the ferrocene group modified cross-linked polymer was synthesized, which exhibited little swollen ratio.
After binding with WP6, formation of side-chain supramolecular cross-linked polymer, the swollen ratio was dramatically improved to more than 25 times. Moreover,
in an acidic environment, the swelled hydrogel could shrink, and this process
exhibited excellent reversibility. Taking advantage of this swelling-shrinking transition, the controlled uptake and release of DOX could be achieved, which might have
potential application as controlled drug delivery systems.
13.4 Conclusion
In summary, the pillar[n]arene-based supramolecular polymer has attracted tremendous attention in the past decade. We could easily construct various pillararenebased supramolecular polymeric assemblies with various topologies and properties
Fig. 28 Illustration of the dramatically promoted swelling by WP6-ferrocene host-guest interactions and subsequently pH-responsive swelling-shrinking transition and application in controlled
drug (DOXÁHCl) release. (Reprinted with permission from Ref. [50]. Copyright © 2016, American
Chemical Society)
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