Thickness Effects of Surface Direct Fluorination and Plasma Modification on Ultra‐High Molecular Weight Polyethylene Ultrathin Membranes

Abstract

For the first time, an ultrathin type of ultra‐high molecular weight polyethylene (UHMWPE) membrane of only 350 nm thickness is surface modified by direct fluorination and plasma treatments. Then a notable suppression in crystallinity is observed. A total of four kinds of thickness, from 350 nm to 6 µm, are investigated to correlate the modification effect on the thickness. Microscopically, the continuous shish‐kebab structure transforms into scattered lamellae clusters. And the damage to the surface morphologies increases as the thickness decreases, yet the resultant contact angles remain almost constant. Especially for the 350 nm thin UHMWPE, the mildest fluorination treatment slightly changes the contact angle, while the multiscale structure changes significantly from crystalline to mesoscopic level. As thickness decreases from 6 µm to 350 nm, the modified volume ratio of membranes increases, and the volumetric modification is almost realized for the 350 nm membrane.

From Basics to Frontiers: A Comprehensive Review of Plasma-Modified and Plasma-Synthesized Polymer Films

“…Moreover, other works show that CO 2 -C 2 H 4 plasma polymerization can result in COOH plasma polymer layers deposited onto polycaprolactone (PCL) nanofibers for diabetic wound healing [117]. -Fluorinated gases and vapors: fluorine (F 2 ) and carbon tetrafluoride (CF 4 ) plasma treatments can introduce fluorine-containing functional groups to improve the adhesion properties of polymer film such as polyethylene [118,119], but can also etch and roughen the surface of polyamide [120]. Furthermore, CF 4 and hexafluoracetone (C 3 F 6 O) are employed in the synthesis of fluorocarbon films with hydrophobic properties [121,122].…”

Engineering Polymer-Based Porous Membrane for Sustainable Lithium-Ion Battery Separators

“…Moreover, this polymer exhibits remarkable impact strength under ordinary ambient conditions and retains robust impact resistance even at low temperatures [ 168 , 169 , 170 , 171 , 172 ]. Notably, the resultant membrane possesses superior microporous structure, exceptional puncture resistance, outstanding mechanical properties, unparalleled chemical resistance, and thermal stability, as well as ultra-high wear and impact resistance [ 173 , 174 , 175 , 176 , 177 ]. Furthermore, these separators are relatively cost-effective, thus enhancing their appeal for large-scale commercial production [ 7 ].…”

“…Notably, UHMWPE has occupied a substantial market share in commercial LIB separators, owing to its superior microporous structure, puncture resistance, mechanical strength, chemical resistance, cost-effectiveness, thermal stability, and so on [ 173 , 174 , 175 , 176 , 177 ]. Just like conventional PE-based components, the performance of a UHMWPE membrane can also be enhanced when used as a battery separator through the introduction of inorganic materials (e.g., SiO 2 , Al 2 O 3 , TiO 2 , and ZrO 2 ) and organic materials (e.g., PVDF, PMMA) to enhance thermal stability and improve the safety of LIBs [ 173 , 180 ].…”