The reversible addition−fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) was carried out successfully in the absence and presence of Lewis acid Y(OTf)3 to synthesize controlled molecular weight atactic and isotactic poly(NIPAM)s using both 1-phenylethyl phenyldithioacetate (PEPD) and cumyl phenyldithioacetate (CPDT) as the RAFT agents. The polymerization rate is about 16 times faster in the presence of the Lewis acid than that in the absence and 1.4 times faster with PEPD than with CPDT as the RAFT agent. The polymer with a higher polydispersity was obtained when prepared in the presence of the Lewis acid than that in the absence. A longer induction period was observed using CPDT than PEPD. The chain-end structure of isotactic poly(NIPAM) was determined by 1H NMR and MALDI−TOF mass spectrometry. The RAFT agent derived isotactic poly(NIPAM) was the main product as expected from the well-accepted mechanism of RAFT polymerization. Moreover, a series of stereoblock [atactic(a)-b-isotactic(i)] poly(NIPAM) with different block lengths were synthesized via a one-pot synthesis procedure:  synthesis of the atactic block in the absence of the Lewis acid followed by the addition of the Lewis acid to synthesize the isotactic block. The longer is the isotactic block length, the higher is the meso dyad value of the stereoblock polymer as expected. We also successfully synthesized the diblock copolymers, a-poly(NIPAM)-b-polystyrene and i-poly(NIPAM)-b-polystyrene, starting with the atactic and isotactic poly(NIPAM) macro-RAFT agents, respectively.

Networked polymers confining an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMImTFSI), were prepared by curing a mixture of bisphenol A diglycidyl ether (BADGE) and tetrafunctional epoxy resins with tetraethylenepentamine (TEPA) in the presence of ionic liquid. It was found that addition of the tetrafunctional epoxy resins was inevitable for better ionic liquid confinement. The ionic liquid confinement, ionic conductivity, mechanical strength, and morphology of the materials strongly depended on the ionic liquid content. At a low ionic liquid content (<40 wt %), the material tightly confined the ionic liquid and showed little ionic conductivity with a high Young’s modulus, while at a high ionic liquid content (>40 wt %), it did not confine the ionic liquid showing higher ionic conductivity with a low Young’s modulus. At a high ionic liquid content (>40 wt %), microphase separation between the ionic liquid and the epoxy networked polymer was observed by scanning electron microscopy (SEM). A transition of the microphase separation from discrete sphere to continuous structure was also observed between 40 wt % and 50 wt % ionic liquid contents. This morphology transition caused a drastic change of the material properties around these ionic liquid contents.

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