- Elings 1601
- Soft and Living Matter Seminar Series
Asymmetric miktoarm star polymers are useful in applications such as thermoplastic elastomers, drug delivery, and ion conduction, but synthetic challenges remain a major issue. I will discuss a new synthetic strategy that simplifies the synthesis of miktoarm star polymers using grafting-through copolymerization to construct the star polymer core. Self-assembly in the bulk was studied as a function of molecular composition, arm stoichiometry, and backbone degree of polymerization (N). Insights generated from scattering experiments and self-consistent field theory simulations indicate these materials behave as disperse mikto-stars at low N with a transition to brush-like conformations as N increases. These conclusions were used to develop a second-generation synthetic strategy wherein asymmetry is introduced by first homopolymerizing a macromonomer followed by efficient termination to install a single disparate type of arm. Experiments and theory confirm that the self-assembly of these materials is controlled by the average number of macromonomer-derived arms, which is easily controlled through reaction stoichiometry. Due to the functional group tolerance of Grubbs catalysis, a wide variety of ABN and A(BA′)N miktoarm star polymers can be produced from different A and B block chemistries that should be useful in a variety of applications.