A series of poly(N-isopropylacrylamide)s (poly(NIPAM)s) have been synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization from a functionalized chain transfer agent (CTA) bearing either dialkoxynaphthalene or dialkoxyphenylene moieties. After demonstrating the controlled character of the RAFT polymerization in the presence of these CTAs, well-defined functionalized poly(NIPAM)s with low PDIs and similar molecular weights were selected and subjected to lower critical solution temperature (LCST) measurements using UV-vis spectroscopy. We have investigated the complexation of the polymers with the tetracationic cyclophane cyclobis(paraquat-p-phenylene) (CBPQT 4+ ) and specifically the role the counter anion (Cl À , Br À , I À ) of the cyclophane has on the LCST. Moreover, we have shown that the addition of a competing end-functionalized naphthalene poly(NIPAM) guest to a (CBPQT 4+ )-endfunctionalized phenylene poly(NIPAM) complex results in the dethreading of the original architecture.

A Thermosensitive polymers exhibiting a lower critical solution temperature (LCST) can be made responsive to pH change by introducing acid or base comonomer units, and the LCST can be switched between higher and lower temperatures as a result of the polarity change of the comonomer units upon their pH--induced protonation or deprotonation. In the present study, we describe a new comonomer design that aims at increasing the magnitude of the pH--triggered LCST shift.Random copolymers of N--isopropylacrylamide and 4--((2--carboxyallyl)oxy)benzoic acid, denoted as P(NIPAM--co--CBA), were synthesized, in which each CBA comonomer unit bears an acrylic acid and a benzoic acid group of similar pKa. With respect to comonomers containing a single acid group, this particular comonomer structure makes it more hydrophobic in the protonated state (pHpKa) due to the doubled charge, which results in larger pH--triggered LCST shift based on the comonomer effect. The demonstrated comonomer design principle, which is general and can also be applied to base comonomers, represents a useful strategy for enhancing the efficiency and sensitivity of the pH--responsiveness of LCST polymers. 15 A rational comonomer design leads to large pH-induced LCST shift.