High Loading Capacity and Wear Resistance of Graphene Oxide/Organic Molecule Assembled Multilayer Film

Abstract

Taking advantage of the strong charge interactions between negatively charged graphene oxide (GO) sheets and positively charged poly(diallyldimethylammonium chloride) (PDDA), self-assembled multilayer films of (GO/PDDA)n were created on hydroxylated silicon substrates by alternating electrostatic adsorption of GO and PDDA. The formation and structure of the films were analyzed by means of water contact angle measurement, thickness measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Meanwhile, tribological behaviors in micro- and macro- scale were investigated by AFM and a ball-on-plate tribometer, respectively. The results showed that (GO/PDDA)n multilayer films exhibited excellent friction-reducing and anti-wear abilities in both micro- and macro-scale, which was ascribed to the special structure in (GO/PDDA)n multilayer films, namely, a well-stacked GO–GO layered structure and an elastic 3D crystal stack in whole. Such a film structure is suitable for design molecular lubricants for MEMS and other microdevices.

Carbon Nanotube-Gold Nanoparticle-Based Self-Powered Electrochemical Biosensors for Highly Sensitive and Stable Detection of Myoglobin

“…In Figure S7E, the double peaks in the N 1s spectrum were able to resolve the two chemical states of nitrogen. The peak with a binding energy of about 400.3 eV was attributed to the free amino group, while the peak with a binding energy of 403.6 eV belonged to the quaternized amino group, which originated from the strongly cationic polyelectrolyte PDDA with positive charge . This indicated that AuNPs could indeed attach to the surface of CNT by electrostatic force, which together with Figure C corroborated the correctness of the electrostatic adsorption mechanism.…”

Fretting wear_lubrication of initially worn parts through tribo-induced anchorage of PTFE in wear scars, and tribochemical creation of graphene oxide

“…Amorphous carbon and graphene based lubricious interface were indeed observed upon tribochemical reactions in contacts lubricated with methane [29], isopropyl alcohol [30], and ethylene glycol [31]. Moreover, graphene oxide has already demonstrated lubricious capabilities in macroscale contacts [32]. The very weak signal collected on the 3 rd body of the cylinder is most likely related to its thinness.…”

Macroscale Ultradurable Antiwear Achieved on Graphene‐Based Films via Multiphase Combination

“…Firstly, APTES‐SAM was constructed on hydroxylated Si substrates according to our previous work. [ 28 ] The detailed preparation processes can be found in the Supporting Information (See SI 2). Subsequently, 100 μL of GO dispersion was spin coated on APTES‐modified Si wafer to obtain GO layer, and then 100 μL of GQDs solution was spin coated on GO layer to obtain (GO/GQDs) 1 film.…”