KES1-0956
Synthesis of Sequence-Controlled Polymer via Anionic Self-Alternating Polymerization
Topic
S1. Polymer Synthesis
When and Where
Sep 30, 2026
15:15 - 15:40
Room 101
Session Chairs
Youn Soo KIM
Presenter(s)
Takashi Ishizone (Institute of Science Tokyo)
Co-Author(s)
Abstract
It is known that the anionic copolymerization of styrene (St) and 1,1-diphenylethylene (DPE) proceeded to afford an alternatingly sequenced copolymer. The non-homopolymerizable property of DPE plays a crucial role to achieve this unique copolymerization behavior. Based on this copolymerization behavior of St and DPE, we designed and synthesized a new AB-type difunctional vinyl monomer, 4-vinyl-1,1-diphenylethylene (VD), comprising conjugated St and DPE frameworks. A series of substituents including chloro (ClVD), methyl (MeVD), methoxy (MeOVD), and dimethylamino (Me2NVD) groups were also introduced at the 4’-position of the VD framework to vary the polymerizability of VD. Anionic polymerization of VD by diphenylmethylpotassium (Ph2CHK) in THF at -78 to 0 °C gave a soluble poly(VD) having a predicted molecular weight and a narrow molecular weight distribution (Mw/Mn ~ 1.2). Similar to VD, ClVD, MeVD, and MeOVD underwent the anionic polymerization to give the soluble polymers with the well-defined chain structures (Mw/Mn = 1.1–1.3). The 1H and 13C NMR measurements and MALDI-TOF-MS analysis revealed that a “self-alternating polymerization” of VD, ClVD, MeVD, and MeOVD yielded a linear homopolymer with an (AB)n-type alternating sequence through the intermolecular cross-propagation chain-growth mechanism. In particular, the resulting poly(ClVD) exhibited only an odd-numbered degree of polymerization, indicating a mechanism of exclusive initiation and subsequent self-alternating polymerization of the VD derivative. In contrast, Me2NVD underwent the usual chemoselective polymerization in the St framework to yield an (A)n-type sequence, because the electrophilicity of the DPE framework of Me2NVD was highly reduced. Thus, the electronic effect of the substituents determines the polymerization behavior of a series of VD derivatives.
