We report a one-pot synthesis of ABC triblock copolymers of poly(ethylene glycol)− (PEG−) polystyrene− (PS−) poly(methyl methacrylate) (PMMA), and poly(ε-caprolactone)− (PCL−) PS−PMMA by combining in situ click [3 + 2] and Diels−Alder [4 + 2] reactions. For this purpose, furan-protected maleimide end-functionalized PMMA, PS with α-anthracene and ω-azide end-functionality, and PEG or PCL with an alkyne end-functional group were reacted in N,N-dimehtylformamide (DMF) for 36 h at 120 °C in order to give the corresponding triblock copolymers. All polymeric precursors with narrow molecular weight distribution and well-defined chain-end functionalities were achieved from living polymerization methods, except PEG. The obtained polymers were characterized by 1H NMR (250 MHz), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) measurements.

Using the Diels−Alder (DA) “click chemistry” strategy between anthracene and maleimide functional groups, two series of well-defined polystyrene-g-poly(ethylene glycol) (PS-g-PEG) and polystyrene-g-poly(methyl methacrylate) (PS-g-PMMA) copolymers were successfully prepared. The whole process was divided into two stages:  (i) preparation of anthracene and maleimide functional polymers and (ii) the use of Diels−Alder reaction of these groups. First, random copolymers of styrene (S) and chloromethylstyrene (CMS) with various CMS contents were prepared by the nitroxide-mediated radical polymerization (NMP) process. Then, the choromethyl groups were converted to anthryl groups via the etherifaction with 9-anthracenemethanol. The other component of the click reaction, namely protected maleimide functional polymers, were prepared independently by the modification of commercially available poly(ethylene glycol) (PEG) and poly(methyl methacrylate) (PMMA) obtained by atom transfer radical polymerization (ATRP) using the corresponding functional initiator. Then, in the final stage PEG and PMMA prepolymers were deprotected by retro-Diels−Alder in situ reaction by heating at 110 °C in toluene. The recovered maleimide groups and added anthryl functional polystyrene undergo Diels−Alder reaction to form the respective (PS-g-PEG) and (PS-g-PMMA) copolymers. The graft copolymers and the intermediates were characterized in detail by using 1H NMR, GPC, UV, fluorescence, DSC, and AFM measurements.

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Hetero‐arm star ABC‐type terpolymers, poly(methyl methacrylate)‐polystyrene‐poly(tert‐butyl acrylate) (PMMA‐PS‐PtBA) and PMMA‐PS‐poly(ethylene glycol) (PEG), were prepared by using “Click” chemistry strategy. For this, first, PMMA‐b‐PS with alkyne functional group at the junction point was obtained from successive atom transfer radical polymerization (ATRP) and nitroxide‐mediated radical polymerization (NMP) routes. Furthermore, PtBA obtained from ATRP of tBA and commercially available monohydroxyl PEG were efficiently converted to the azide end‐functionalized polymers. As a second step, the alkyne and azide functional polymers were reacted to give the hetero‐arm star polymers in the presence of CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) in DMF at room temperature for 24 h. The hetero‐arm star polymers were characterized by 1H NMR, GPC, and DSC. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5699–5707, 2006