Saeed Ebtisam, Piñeiro Manuel M, Hermida-Merino Carolina, Pastoriza-Gallego María José
Chemistry and Physics Department, Faculty of Science, Beni-Suef University, Beni Suef 62511, Egypt.
Departamento de Física Aplicada, Fac. de Ciencias, Univ. de Vigo, Vigo 36310, Spain.
Nanomaterials (Basel). 2019 Feb 12;9(2):252. doi: 10.3390/nano9020252.
Suspensions of nanometric-sized graphene platelets have been proposed recently as potential heat exchange working fluids, due to their remarkably enhanced thermal profile. Nevertheless, their use presents serious long-term stability issues. Due to this limitation, the nanoplatelets surface chemical functionalization has been postulated as a promising alternative to solve this problem. In this work, graphene nanoplatelets were functionalized following an oxidation-reduction process, and then dispersed in glycol as base fluid. The nanoparticles chemical profile was determined using XPS (x-ray photoelectron spectroscopy). The thermo-physical properties characterization of these nanofluids was performed by determining their viscosity and thermal conductivity, because of their impact on practical applications related with fluid flow and heat transfer. The effect of temperature and shearing time on viscosity were analyzed. Viscosity was measured with a stress-controlled rheometer. All samples show shear-thinning behavior with a very remarkable influence of temperature in their viscoelastic profile.
由于其显著增强的热特性，纳米尺寸的石墨烯片悬浮液最近被提议作为潜在的热交换工作流体。然而，它们的使用存在严重的长期稳定性问题。由于这一限制，纳米片表面化学功能化被认为是解决该问题的一种有前途的替代方法。在这项工作中，石墨烯纳米片通过氧化还原过程进行功能化，然后分散在乙二醇中作为基础流体。使用X射线光电子能谱（XPS）确定纳米颗粒的化学特征。由于这些纳米流体的粘度和热导率对与流体流动和传热相关的实际应用有影响，因此通过测定它们的粘度和热导率来进行热物理性质表征。分析了温度和剪切时间对粘度的影响。用应力控制流变仪测量粘度。所有样品均表现出剪切变稀行为，温度对其粘弹性特征有非常显著的影响。
