Currently, ion-responsive molecularly imprinted polymers are rarely reported. As mentioned
above, the PNIPAm-based hydrogels undergo volume changes in response to the ionic
strength, leading to ion-responsive binding properties. Intriguingly, Chu et al. reported
a molecular-recognition microcapsule for ion-responsive controlled release, which may bring
us some inspirations for the preparation of ion-responsive MIPs [115]. The reported
ion-responsive microcapsule is composed of a core-shell porous membrane and linear grafted poly
(N-isopropylacrylamide-co-benzo-18-crown[6]-acrylamide) (PNIPAm-co-PBCAm) chains in the pores
acting as molecular-recognition gates. Benzo-18-crown[6] acrylamide (BCAm) is a crown ether