Chlanda Adrian, Walejewska Ewa, Kowiorski Krystian, Heljak Marcin, Swieszkowski Wojciech, Lipińska Ludwika
Łukasiewicz Research Network, Institute of Microelectronics and Photonics, Department of Chemical Synthesis and Flake Graphene, Aleja Lotników 32/46, 02-668, Warsaw, Poland.
Warsaw University of Technology, Faculty of Materials Science and Engineering, Biomaterials Group, Wołoska 141, 02-507, Warsaw, Poland.
Micron. 2021 Jul;146:103072. doi: 10.1016/j.micron.2021.103072. Epub 2021 Apr 19.
We decided to implement an extensive atomic force microscopy study in order to get deeper understanding of surface-related nanoscale properties of 3D printed pristine polycaprolactone and its reduced-graphene-oxide-loaded composites. The study included surface visualization and roughness quantification, elastic modulus and adhesion force assessment with force spectroscopy, along with kelvin probe force microscopy evaluation of local changes of surface potential. Atomic force microscopy examination was followed by scanning electron microscopy visualization and wettability assessment. Moreover, systematic examination of reduced graphene oxide flakes fabricated exclusively for this study was performed, including: scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and combustion elemental analysis. The addition of reduced graphene oxide resulted in thickening of the composite fibers and surface roughness enhancement. In addition, elastic modulus of composite fibers was higher and at the same time adhesion forces between scanning probe and tested surface was lower than for pristine polymeric ones. Lastly, we recorded local (nanoscale) alterations of surface potential of fibers with addition of graphene-derivative. The results clearly suggest graphene derivative's dose-dependent alteration of elastic modulus and adhesion force recorded with atomic force microscope. Moreover, changes of the material's surface properties were followed by changes of its electrical properties.
我们决定开展一项广泛的原子力显微镜研究，以便更深入地了解3D打印的原始聚己内酯及其负载还原氧化石墨烯的复合材料的表面相关纳米尺度特性。该研究包括表面可视化和粗糙度量化、通过力谱评估弹性模量和粘附力，以及利用开尔文探针力显微镜评估表面电位的局部变化。在进行原子力显微镜检查之后，进行了扫描电子显微镜可视化和润湿性评估。此外，还对专门为本研究制备的还原氧化石墨烯薄片进行了系统检查，包括：扫描电子显微镜、拉曼光谱、X射线光电子能谱和燃烧元素分析。还原氧化石墨烯的添加导致复合纤维变粗且表面粗糙度增加。此外，复合纤维的弹性模量更高，同时扫描探针与测试表面之间的粘附力低于原始聚合物纤维。最后，我们记录了添加石墨烯衍生物后纤维表面电位的局部（纳米尺度）变化。结果清楚地表明，原子力显微镜记录的石墨烯衍生物对弹性模量和粘附力具有剂量依赖性变化。此外，材料表面性质的变化伴随着其电学性质的变化。
