Facile Synthesis of Functional Poly(ε-caprolactone) via Janus Polymerization

Janus Polymerization: A One‐Shot Approach towards Amphiphilic Multiblock Poly(ester‐acetal)s Directly from 1,3‐Dioxolane with ε‐Caprolactone

“…Only the methylene protons of CL and DO neighboring the terminal hydroxyl groups shift from δ 3.54 to δ 4.54 after TFA treatment (Figures 1A, 1E, S2 and S16), which reveals that PO is located in the polymer backbone rather than at one end as the common result of initiating CROPs. [ 17 ] In addition, DOSY NMR analyses confirm the copolymerization of DO and CL in one chain since the diffusion coefficients of DO (H b and H e ) and CL (H d , H g , H h and H k ) segments are identical (0.52 × 10 –10 m 2 /s) (Figures 3C and S17). The random copolymer catalyzed by Nd(OTf) 3 /PO (Sample 10 in Table 1) demonstrates methyne protons of PO initiating residues at chain ends (H a at δ 4.0), which are coupled to methyl (H c , δ 1.24) and methylene (H s , δ 3.75) (Figures 1C, S4, S18 and S19).…”

“…[ 14‐16 ] Janus polymerization is a facile strategy to convert monomers to well‐defined di‐ and multi‐block copolymers directly in one step generating the hydrophobic plastic elastomers [PCL‐ b ‐P(CL‐ co ‐THF)] m , PCL‐ b ‐P(CL‐ co ‐3,3‐bis(chloromethyl) oxacyclobutane) (PCL‐ b ‐P(CL‐ co ‐CO)) and other topologic polymers. [ 17‐20 ] More applicable monomers are necessary for the construction of versatile MBCPs with desired properties, for instance, hydrophilicity and stimuli‐responsive behaviors. [ 13,21 ]…”