Anionic Polymerization

Anionic polymerization is the classical “living” polymerization: the first discovered (in 1956), and still the most widely practiced. Today, the most common initiators are isomers of butyllithium; in our laboratory, we routinely use anionic polymerization to prepare homopolymers and block copolymers from dienes (butadiene, isoprene), styrenes (styrene, methylstyrene), and alkylmethacrylates (alkyl = methyl, butyl, hexyl, 2-ethylhexyl…). Complex macromolecular architectures such as starblocks can be created by reacting the living ends with a suitable multifunctional coupling agent, such as the chlorosilane shown below, which yields six-arm starblock copolymers.

Starblock GPC
Synthetic scheme and GPC traces (bottom left) for a (PB-PS-PI)6 starblock copolymer. Top and right: butadiene polymerization to essential completion (blue GPC trace), followed by styrene polymerization (green GPC trace), followed by isoprene polymerization (red GPC trace), followed by chlorosilane coupling to yield the desired 6-arm starblock (black GPC trace) in high yield (work of Adam Burns).

Supported by the National Science Foundation, Polymers Program, and Materials Research Science and Engineering Center (MRSEC) Program, through the Princeton Center for Complex Materials

Current/Recent Group Members Employing Anionic Polymerization, and Their Project Titles:

Dane Christie PhD *19 – “Influence of Confinement and Interfaces on the Structure and Dynamics of Amorphous Polymers”
Will Mulhearn PhD *18 – “Melt-Miscibility in Block Copolymers Containing Polyethylene”
Adam Burns PhD *17 – “Thermoplastic Elastomers with Composite Crystalline-Glassy Hard Domains via Crystallization from a Single-Phase Melt”
Raleigh Davis PhD *15 – “Shear Alignment of Block Copolymer Thin Films to Produce Well-Ordered Microdomains for Use in Nanofabrication”
Bryan Beckingham PhD *13 – “Mixing Thermodynamics of Block-Random Copolymers”
Ha-Kyung Kwon ‘13 – “Synthesis and Characterization of Polystyrene-block-Poly(2-ethylhexylmethacrylate) Diblock Copolymers”
Brian Michal ‘10 – “Synthesis and Characterization of Polystyrene-Poly(n-hexylmethacrylate) Diblock Copolymers”

Selected Recent Publications:

R.L. Davis, P.M. Chaikin, and R.A. Register, "Cylinder Orientation and Shear-Alignment in Thin Films of Polystyrene-Poly(n-hexylmethacrylate) Diblock Copolymers", Macromolecules, 47, 5277-5285 (2014).

H.-K. Kwon, V.E. Lopez, R.L. Davis, S.Y. Kim, A.B. Burns, and R.A. Register, "Polystyrene-Poly(2-ethylhexylmethacrylate) Block Copolymers: Synthesis, Bulk Phase Behavior, and Thin Film Structure", Polymer, 55, 2059-2067 (2014).

B.S. Beckingham and R.A. Register, "Architecture-Induced Microphase Separation in Nonfrustrated A-B-C Triblock Copolymers", Macromolecules, 46, 3486-3496 (2013).

B.S. Beckingham and R.A. Register, "Synthesis and Phase Behavior of Block-Random Copolymers of Styrene and Hydrogenated Isoprene", Macromolecules, 44, 4313-4319 (2011).