基于分子动力学的丝网印刷柔性传感器电极导电性机理研究

目的 研究提高丝网印刷柔性传感器电极的导电性，为提升柔性传感器的电学性能提供参考依据。方法 首先采用分子动力学（Molecular Dynamic,MD）模拟方法，建立在Wenzel模型下导电银浆团簇在不同粗糙因子下的对苯二甲酸乙二醇酯（Polyethylene Terephthalate,PET）表面铺展的分子动力学模型，其次分别计算各体系下的结合能，用以表征不同体系下PET表面对导电银浆团簇结合能力，接下来通过丝网印刷实验的方法探究银浆与不同粗糙因子PET的结合能力对传感器电极的导电性的影响。结果 仿真结果表明，导电银浆团簇在不同粗糙因子的PET表面的铺展过程中会陷入粗糙表面的凹陷处，且导电银浆与基材的结合能随着PET粗糙因子的增加而增加。实验结果表明，使用不同粗糙因子的PET作为承印物能显著提升电极的导电性。相比于未处理的PET，随着粗糙因子的增加，导电线条的电导率逐渐升高，电阻率逐渐降低，方块电阻逐渐降低。电导率最大提升了77%，电阻率最大下降了43%，方块电阻最大下降了38%。结论 导电银浆在粗糙表面铺展的过程中会渗入基材的凹陷处，增加了吸附点位，使得银浆与基材的结合更加紧密...

Mechanism of Electrode Conductivity in Screen Printing Flexible Sensors Based on Molecular Dynamics

The work aims to improve the conductivity of the electrode in the screen printing flexible sensor, and provide a reference for improving the electrical properties of the flexible sensor. Firstly, the molecular dynamic (MD) simulation method was used to establish the molecular dynamics model of conductive silver paste spreading on the surface of polyethylene terephthalate (PET) under different roughness factors in Wenzel model. Secondly, the binding energy of each system was calculated to characterize the binding ability of PET surface to conductive silver paste clusters in different systems. Then, the effect of the binding ability of silver paste and PET with different roughness factors on the conductivity of sensor electrode was explored by screen printing experiment. The simulation results showed that the conductive silver paste fell into the depression of rough surface during the spreading on PET surface with different roughness factors, and the binding energy between conductive silver paste and substrate increased with the increase of PET roughness factors. According to the experimental results, the conductivity of the electrode was significantly improved by PET with different roughness factors as the substrate. Compared with untreated PET, with the increase of roughness factor, the conductivity of conductive lines gradually increased by 77%, the resistivity gradually decreased by 43%, and the block resistance gradually decreased by 38%. Conductive silver paste will penetrate into the depression of the substrate during the spreading on rough surface, which increases the adsorption point, making the combination of silver paste and substrate closer, narrowing the distance between silver particles and enhancing the conductivity. Therefore, in order to increase the conductivity of the conductive lines, the roughness of the substrate can be appropriately increased.