Convenient Access to α‐Amino‐ω‐Hydroxyl Heterobifunctional PEG and PPO via a Sacrificial Hexahydro‐Triazine Star Strategy

Noncovalent Protection for Direct Synthesis of α-Amino-ω-hydroxyl Poly(ethylene oxide)

The synthesis of poly(ethylene oxide) (PEO) with amino end group, a key functionality for PEGylation, is a long-standing challenge. Multistep routes based on postmodification or covalent protection have been adopted to circumvent ethoxylation of the amino group by ethylene oxide (EO). Here, we report a noncovalent protection strategy for one-step synthesis of PEO amine. An amino (di)alcohol is mixed with a small amount of mild phosphazene base and excess triethylborane (Et₃B) before addition of EO. The complexation of the amino group with Et₃B guarantees that polymerization of EO occurs selectively from the hydroxyl group through the bicomponent metal-free catalysis. Simply by precipitation in diethyl ether, the protective Et₃B as well as the catalyst can be removed to afford α-amino-ω-hydroxyl PEO with controlled molar mass, low dispersity, and complete end functionality. The effect of initiator structure and retention of Et₃B on the storage (oxidative) stability of PEO amine is also revealed.

Surface-Conformal Triboelectric Nanopores via Supramolecular Ternary Polymer Assembly

A triboelectric nanogenerator (TENG) is of tremendous interest owing to its high energy efficiency with a simple device architecture and applicability to various materials. Most previous topological surface modifications introduced for further improving the performance of a TENG are detrimental because they require expensive and/or harsh (e.g., high temperature and acidity) postetching processes, which limit the material choice and design of its components. Herein, we demonstrate an one-step route for developing rapid wet-processable surface-conformal triboelectric nanoporous films (STENFs). Our method is based on a simple supramolecular assembly of a ternary polymer blend suitable for various conventional solution processes such as spin-, bar-, spray-, and dip-coating. The one-step wet process of a ternary solution produces thin large-area films in which self-assembled, ordered nanopores of approximately 33 nm in diameter are developed even without an additional etching process. The study reveals that the small amount of amine-terminated poly(ethylene oxide) added to the binary blend of sulfonic-acid-terminated poly(styrene) and poly(2-vinylpyridine) efficiently activates the formation of spontaneous nanopores as a pore-generating agent. Our STENF significantly enhances the open-circuit voltage up to 1.5 times higher than that of a planar one, leading to an improved power density of approximately 77 μW/cm². The suitability for diverse conventional coating processes offers a convenient approach for fabricating high-performance STENFs not only on flat substrates such as metals, polymers, and oxides but also on topological ones including wrinkled, roughened surfaces, textile fibers, natural leaves, and fabrics over a large area.