화학공학소재연구정보센터
Reactive & Functional Polymers, Vol.132, 60-73, 2018
Controlled ROMP synthesis of side-chain ferrocene and adamantane-containing diblock copolymer for the construction of redox-responsive micellar carriers
We present the controlled synthesis of the polynorbornene-based well-defined block copolymer PNFc-b-PNAd side-chain containing ferrocene (Fc) and adamantane (Ad) units by the ring-opening metathesis polymerization using the 3rd generation Grubbs catalyst. A polycationic amphiphilic block copolymer PNFcium-b-PNAd was then fabricated by the stoichiometric oxidation of Fc into ferricinium (Fcium) cations, and its redox-controlled reversible self-assembly behavior in water was demonstrated by SEM and DLS with glutathione as reductant and FeCl3 as oxidant. By using benzocaine (BA) as model cargo, the loading ability of the cationic micelles formed by PNFcium-b-PNAd was investigated and confirmed, and the reduction of Fcium could lead to the rapid release of loaded payloads. A new supramolecular copolymer PNFc-b-PNAd@beta-CD was further prepared by simply mixing PNFc-b-PNAd and beta-cyclodextrin (B-CD) with equimolar quantity to Ad units, in which host-guest interactions were mainly observed between beta-CD and pendant Ad. Owing to the formation of hydrophilic inclusion complexes, PNFc-b-PNAd@beta-CD possesses amphiphilic property and exhibits redox-controlled self-assembly behavior in water, too. The oxidation-triggered release of loaded-BA from the supramolecular micelles was observed in a slow and durable way. The present novel redox-responsive micelles provide innovative examples of rational design for stimuli-responsive carriers by using Fc-containing polymers.