Luceño-Sánchez Jose Antonio, Maties Georgiana, Gonzalez-Arellano Camino, Diez-Pascual Ana Maria
Departamento de Química Analítica, Química Física e Ingeniería Química, Facultad de Ciencias, University of Alcalá, E-28871 Madrid, Spain.
Departamento de Química Orgánica y Química Inorgánica, Facultad de Ciencias, University of Alcalá, E-28871 Madrid, Spain.
Nanomaterials (Basel). 2018 Oct 23;8(11):870. doi: 10.3390/nano8110870.
Graphene oxide (GO), the oxidized form of graphene, shows unique properties including high mechanical strength, optical transparency, amphiphilicity and surface functionalization capability that make it attractive in fields ranging from medicine to optoelectronic devices and solar cells. However, its insolubility in non-polar and polar aprotic solvents hinders some applications. To solve this issue, novel functionalization strategies are pursued. In this regard, this study deals with the preparation and characterization of hexamethylene diisocyanate (HDI)-functionalized GO. Different reaction conditions were tested to optimize the functionalization degree (FD), and detailed characterizations were conducted via elemental analysis, Fourier-transformed infrared (FT-IR) and Raman spectroscopies to confirm the success of the functionalization reaction. The morphology of HDI-GO was investigated by transmission electron microscopy (TEM), which revealed an increase in the flake thickness with increasing FD. The HDI-GO showed a more hydrophobic nature than pristine GO and could be suspended in polar aprotic solvents such as ,-dimethylformamide (DMF), -methylpyrrolidone (NMP) and dimethyl sulfoxide (DMSO) as well as in low polar/non-polar solvents like tetrahydrofuran (THF), chloroform and toluene; further, the dispersibility improved upon increasing FD. Thermogravimetric analysis (TGA) confirmed that the covalent attachment of HDI greatly improves the thermal stability of GO, ascribed to the crosslinking between adjacent sheets, which is interesting for long-term electronics and electrothermal device applications. The HDI-GO samples can further react with organic molecules or polymers via the remaining oxygen groups, hence are ideal candidates as nanofillers for high-performance GO-based polymer nanocomposites.
氧化石墨烯（GO）是石墨烯的氧化形式，具有独特的性能，包括高机械强度、光学透明度、两亲性和表面功能化能力，这使其在从医学到光电器件和太阳能电池等领域具有吸引力。然而，它在非极性和极性非质子溶剂中的不溶性阻碍了一些应用。为了解决这个问题，人们探索了新的功能化策略。在这方面，本研究涉及六亚甲基二异氰酸酯（HDI）功能化GO的制备和表征。测试了不同的反应条件以优化功能化程度（FD），并通过元素分析、傅里叶变换红外（FT-IR）和拉曼光谱进行了详细表征，以确认功能化反应的成功。通过透射电子显微镜（TEM）研究了HDI-GO的形态，结果表明随着FD的增加，薄片厚度增加。HDI-GO比原始GO具有更强的疏水性，可以悬浮在极性非质子溶剂如N，N-二甲基甲酰胺（DMF）、N-甲基吡咯烷酮（NMP）和二甲基亚砜（DMSO）以及低极性/非极性溶剂如四氢呋喃（THF）、氯仿和甲苯中；此外，随着FD的增加，分散性得到改善。热重分析（TGA）证实，HDI的共价连接大大提高了GO的热稳定性，这归因于相邻片层之间的交联，这对于长期电子和电热器件应用来说很有意义。HDI-GO样品可以通过剩余的氧基团进一步与有机分子或聚合物反应，因此是基于GO的高性能聚合物纳米复合材料的理想纳米填料候选物。
