Polymerization of N‑Substituted Glycine <i>N</i>‑Thiocarboxyanhydride through Regioselective Initiation of Cysteamine: A Direct Way toward Thiol-Capped Polypeptoids

Because of the high reactivity, <i>N</i>-carboxyanhydride (NCA) can be initiated by the thiol group. On the contrary, <i>N</i>-thiocarboxy­anhydride (NTA) is more stable and is able to tolerate it. Herein, we apply cysteamine as a regioselective initiator for ring-opening polymerization (ROP) of N-substituted glycine <i>N</i>-thiocarboxy­anhydride (NNTA) to synthesize well-defined thiol-capped polypeptoids. ROPs of sarcosine NTA (Sar-NTA) and <i>N</i>-ethylglycine NTA (NEG-NTA) are well controlled when [M]/[I] ≤ 100 with high yields (>87.5%) producing polypeptoids with designable molecular weights and low polydispersity indices (<1.2). All the polypeptoid chains contain a thiol end group, which is confirmed by NMR analyses, MALDI-ToF MS spectra, and Ellman’s assay. Through radical-mediated thiol–ene reaction with styrene, all the thiol chain ends are transferred to oligostyrene, revealing the convenience of further modification. Benefiting from the thiol–ene click chemistry, thiol-capped polysarcosine (PSar) and poly­(<i>N</i>-ethylglycine) (PNEG) are promising candidates to replace PEG for their nontoxicity and biocompatibility

Hydroxyl Group Tolerated Polymerization of N‑Substituted Glycine <i>N</i>‑Thiocarboxyanhydride Mediated by Aminoalcohols: A Simple Way to α‑Hydroxyl-ω-aminotelechelic Polypeptoids

<i>N</i>-Carboxyanhydride (NCA) polymerization cannot tolerate nucleophilic groups that have the ability of initiation, e.g., hydroxyl group. In contrast, <i>N</i>-thiocarboxyanhydride (NTA) is a much more stable monomer to tolerate them. In this contribution, we investigate aminoalcohols including 2-amino-1-ethanol (<b>AE</b>), 3-amino-1-propanol (<b>AP</b>), 4-amino­methylbenzyl alcohol (<b>AMB</b>), 6-amino-1-hexanol (<b>AH</b>), and 12-amino-1-dodecanol (<b>AD</b>) as initiators for ring-opening polymerization of N-substituted glycine <i>N</i>-thiocarboxyanhydride (NNTA) to prepare α-hydroxyl-ω-aminotelechelic water-soluble polypeptoids. Hydroxyl groups of <b>AE</b>, <b>AP</b>, and <b>AMB</b> are activated by hydrogen bonding with amino groups, which results in a mixture of α,ω-diaminotelechelic and α-hydroxyl-ω-amino­telechelic polypeptoids confirmed by ¹H NMR, MALDI-ToF, and SEC measurements. Pure α-hydroxyl-ω-amino­telechelic polypeptoids are synthesized for the first time initiated by <b>AH</b> and <b>AD</b> with controlled molecular weights (1.3–12.4 kg/mol) and low polydispersity indices (<1.30). Hydroxyl groups in <b>AH</b> and <b>AD</b> remain inactive to generate hydrogen bonding due to the long distance from amino groups. Water-soluble polypeptoids with special functional end groups are attractive alternatives of PEG for their nontoxicity and biocompatibility having great potential in biomedical applications

Regulation of dewetting and morphology evolution in spin-coated PS/PMMA blend films via graphene-based Janus nanosheets

Spin-coated blend films with complex phase-separated morphology find broad applications while precise tailoring of the morphology is still challenging. In this study, graphene oxide (GO)-based Janus nanosheets were synthesized by interfacial polymerization in a GO nanosheet stabilized Pickering emulsion with polystyrene (PS) and poly(hydroxyethyl methacrylate) synchronously being grafted to the GO nanosheet from the oil and water sides. The Janus nanosheets make the morphology of spin-coated PS/poly(methyl methacrylate)(PMMA) blend films tunable over the full height of the film until the substrate as their preferential assembly at the PS/PMMA interface and attachment on the glass substrate drive the top PS phase to migrate towards the substrate and the bottom PMMA phase to dewet from the substrate towards the air. By varying blend composition and Janus nanosheet loading, morphologies are readily transformed from a PS network on top of PMMA to PS droplets in the PMMA matrix and from PS encapsulated by PMMA to PMMA cavities in the PS network, etc.. This enables generating thin films with various morphologies ranging from a flat surface to cavity-network structures, droplet-matrix structures or bi-continuous structures, etc. at will. Moreover, the morphologies trapped by jammed nanosheets at the interface are super stable against further evolution upon annealing