A general strategy through the use of direct azidation of alcohols allowed the sequence control of macromers via both the iterative sequential growth and iterative exponential growth methods. The chemistry was highly efficient in building polymers from a sequence of compositionally different macromers tethered together in close proximity. Using the DPPA/DBU method for near quantitative azidation of the benzyl alcohol moiety, sequence controlled polymers were made via a direct and one-step procedure for CuAAC activation. With four different macromers, spherical miktoarm star-like polymers of 50,000 molecular weight were prepared with a low dispersity, and the polymer coil size depended on the type of added macromer. Polymers made via the iterative methods opens the way for the design of advanced materials with predictable properties.<br/><br/>Sequential growth of multifunctional telechelic polymer chains was used here to produce three, four or seven HO-functionalities equally spaced along the polymer backbone. The telechelic building block consisted of a halide group on one end and both a hydroxyl and alkyne group on the other end. The key was to maintain the halide end-group on the telechelic polymer chain during the CuAAC coupling reaction after each sequential growth. The HO-functionalities were then converted to azide groups allowing further CuAAC reactions with either alkyne polymeric dendrons and cyclics to produce equally spaced grafts along the backbone. The relative hydrodynamic volume ratio of these grafted structures to their corresponding linear analogues were lower but similar to that found from the graft (i.e. dendron or cyclic) itself.

Sequence control of macromers via iterative sequential and exponential growth

254th National Meeting (2017)

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