The article titled, "Hemisilicone (PM2E) Elastomers: Assessing Prepolymer SyntheticStrategies" was published April 21st, 2026 in ACS, Macromolecules. This paper was co-authored by *Shota Fujii, *Shiqi Liu, *Pei Bian, *Tom McCarthy.
Mr. Fujii writes: "Hemisilicone (−(SiMe2–O–SiMe2–CH2CH2)ₙ–(PM2E)) emerges as a compelling alternative to conventional PDMS for advanced elastomer applications. This study introduces a controlled anionic ring-opening polymerization (AROP) strategy that enables precise regulation of both α- and ω-chain end functionalities via in situ–generated lithium silanolate initiators. The polymerization proceeds cleanly, avoiding back biting and chain transfer, and yields PM2E with narrow molecular weight distributions. Mechanical evaluation reveals that elastomers derived from AROP-synthesized PM2E exhibit exceptional performance, including stretchability exceeding 1000% strain and superior tear resistance. In contrast, elastomers prepared from equilibrated, polydisperse PM2E show similar extensibility but markedly reduced toughness. Overall, this work establishes a robust synthetic platform for producing well-defined, impurity-free hemisilicones with enhanced mechanical properties, highlighting their strong potential as next-generation silicone elastomers."