Spin-Probe Analysis of Graphene Oxide Membranes: Determining Orientational Order from Room-Temperature EPR Spectra with Interfering Signals

Abstract The internal architecture of graphene oxide membranes (GOMs) strongly influences their functional properties. We previously developed a quantitative spin-probe method for determining the orientational order of oxidized graphene layers within GOMs. So far, this method has been applied only to EPR spectra recorded at low temperatures, where the rotational mobility of the probes is effectively suppressed. Here, we present a computational approach for analyzing room-temperature EPR spectra. These spectra have narrower lines and a more pronounced angular dependence, allowing the orientational order of GOMs to be determined more accurately. A weighted least-squares procedure allows the weak spin-probe signal to be extracted in the presence of the much more intense intrinsic EPR signal of graphene oxide.