Elejalde-Cadena Nerith R, Moreno Abel
Instituto de Química, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Alcaldía Coyoacán, Ciudad de México 04510, México.
ACS Omega. 2021 Mar 12;6(11):7887-7895. doi: 10.1021/acsomega.1c00478. eCollection 2021 Mar 23.
In this work, we present an investigation of the surface area and roughness of different dinosaur eggshells of 70 million years old using fractal dimension analysis obtained from atomic force microscopy (AFM) and scanning electron microscopy (SEM) information. We also conduct qualitative analyses on the external and inner surfaces of eggshells, which are mainly composed of calcium carbonate. The morphological characteristics of both surfaces can be revealed by both SEM and AFM techniques. It is observed that the inner surface of the eggshell has greater roughness that increases the surface area due to the vaster number of pores compared to the external face, making, therefore, the fractal dimension also greater. The aim of this contribution is to identify the morphology of the pores, as well as the external and inner surfaces of the eggshells, since the morphology is very similar on both surfaces and will otherwise be difficult to determine with the naked eye by SEM and AFM. In addition, the sole AFM analysis is very complicated for these types of samples due to the intrinsic roughness. However, it needs additional methods or strategies to complete this purpose. This contribution used the fractal dimension to show the same behavior obtained in both SEM and AFM techniques, indicating the fractal nature of the structures.
在这项工作中，我们利用原子力显微镜（AFM）和扫描电子显微镜（SEM）信息获得的分形维数分析，对有着七千万年历史的不同恐龙蛋壳的表面积和粗糙度进行了研究。我们还对主要由碳酸钙构成的蛋壳内外表面进行了定性分析。蛋壳内外表面的形态特征均可通过SEM和AFM技术揭示。据观察，蛋壳内表面粗糙度更大，由于其孔隙数量比外表面更多，因而增加了表面积，所以其分形维数也更大。本研究的目的是识别蛋壳孔隙以及内外表面的形态，因为两者表面形态非常相似，否则很难通过SEM和AFM用肉眼确定。此外，由于这些样品固有的粗糙度，仅靠AFM分析非常复杂。然而，需要额外的方法或策略来实现这一目的。本研究利用分形维数来展示在SEM和AFM技术中获得的相同结果，表明了结构的分形性质。
