Surface confinement induced amorphization of polyethylene oxide in high-performance porous polyethylene films. (5th March 2021)

• Record Type: Journal Article
• Authors: Thitisomboon, Wadeelada; Gu, Qiao; Weng, Lu-Tao; Gao, Ping
• Is Part Of: Polymer. Volume 217(2021)
• Publication Date: 2021-03-05
• Subjects: PEO-PPO-PEO -- UHMWPE -- Surface confinement -- Amorphization; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.123449
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: We report a new nanoconfinement phenomenon whereby surface confinement leads to the amorphization of polyethylene oxide (PEO) in porous ultrahigh molecular weight polyethylene membrane (UHMWPE). The surface confinement was achieved through a monolayer attachment of PEO onto the UHMWPE nanofibril surfaces‒pore bounding edges‒in the membrane via amphiphilic interactions of polypropylene oxide (PPO) blocks in the triblock copolymer of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO). Full amorphization of PEO is corroborated through the lack of phase transitions under differential scanning calorimetry (DSC), and liquid-like vibrational absorption responses under Fourier transform infrared spectroscopy (FTIR). Monolayer confinement of PEO in the membrane is quantified using a combination of Brunauer-Emmett-Teller (BET), time-of-flight secondary ion mass spectrometry (ToF-SIMS) molecular depth profiling and scanning electron microscopy (SEM). The total amount of PEO confined in the porous membrane is 7.7 wt% agreeing with that expected from the total BET surface area of the UHMWPE membrane; ToF-SIMS depth profiling using argon cluster ion reveals the homogeneous PEO distribution along the membrane depth; and surface topology analysis by SEM shows no obvious topological changes after PEO confinement. Graphical abstract: Image 1 Highlights: Surface-confinement of PEO on nanofibrils of UHMWPE membrane leads to amorphization. Unique confinement crystallization mechanisms from the monolayer confinement of PEO. Stable monolayer confinement of PEO on polyethylene nanofibrils via van der Waals. Amorphization of PEO is highly desirable in solid-state battery application.