Shtein Michael, Pri-Bar Ilan, Varenik Maxim, Regev Oren
†Ilse Katz Institute for Nanoscale Science and Technology and ‡Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
Anal Chem. 2015 Apr 21;87(8):4076-80. doi: 10.1021/acs.analchem.5b00228. Epub 2015 Mar 30.
The rapid increase in graphene-based applications has been accompanied by novel top-down manufacturing methods for graphene and its derivatives (e.g., graphene nanoplatelets (GnPs)). The characterization of the bulk properties of these materials by imaging and surface techniques (e.g., electron microscopy and Raman spectroscopy) is only possible through laborious and time-consuming statistical analysis, which precludes simple and efficient quality control during GnP production. We report that thermogravimetry (TG) may be utilized, beyond its conventional applications (e.g., quantification of impurities or surfactants, or labile functional groups) to characterize bulk GnP properties. We characterize the structural parameters of GnP (i.e., defect density, mean lateral dimension, and polydispersity) by imaging and surface techniques, on one hand, and by a systematic TG, on the other. The combined data demonstrate that the combustion temperature of commercially available and laboratory-prepared GnPs is correlated with their mean lateral dimension and defect density, while the combustion temperature range is proportional to their polydispersity index. Mapping all these parameters allows one to evaluate the GnPs' structure following a simple thermogravimetric experiment (without necessitating further statistical analysis). Finally, TG is also used to detect and quantify different GnP constituents in powder and to conduct rapid quality-control tests during GnP production.
基于石墨烯的应用迅速增加，与此同时出现了用于石墨烯及其衍生物（例如石墨烯纳米片（GnP））的新型自上而下制造方法。通过成像和表面技术（例如电子显微镜和拉曼光谱）对这些材料的整体性质进行表征，只能通过费力且耗时的统计分析来实现，这使得在GnP生产过程中无法进行简单而有效的质量控制。我们报告称，热重分析法（TG）除了其传统应用（例如杂质或表面活性剂、或不稳定官能团的定量）之外，还可用于表征GnP的整体性质。一方面，我们通过成像和表面技术来表征GnP的结构参数（即缺陷密度、平均横向尺寸和多分散性），另一方面，通过系统的热重分析法来表征。综合数据表明，市售和实验室制备的GnP的燃烧温度与其平均横向尺寸和缺陷密度相关，而燃烧温度范围与其多分散指数成正比。绘制所有这些参数能够让人们通过简单的热重实验评估GnP的结构（无需进一步的统计分析）。最后，热重分析法还用于检测和定量粉末中不同的GnP成分，并在GnP生产过程中进行快速质量控制测试。
