Chen Jiachen, Yang Jin, Zhou Mingyong, Weng Can
College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China.
Micromachines (Basel). 2021 May 29;12(6):636. doi: 10.3390/mi12060636.
When the part geometry scaling down from macro to microscale level, the size-induced surface effect becomes significant in the injection molding process. The adhesion between polymer and nickel (Ni) mold insert during the process can lead to defects in necking, warping and deformation of microstructure. In this study, the self-assembled monolayers (SAMs) with low surface energy were deposited on the Ni surface to reduce the adhesion and further improve the demolding quality of the microstructure. Results show that the alkyl mercaptan SAMs with chemical bonds and close alignment can be successfully deposited on the surface of Ni by the solution deposition method. The contact angle, surface free energy, and friction coefficient before and after anti-adhesion treatment on the surface of mold insert were measured. In addition, the anti-adhesion properties of different alkyl mercaptan materials and the correspondingly replication quality of microstructure parts after injection molding were analyzed. It is found that the Ni mold insert treated by the perfluorodecanethiol has the best wear resistance and still shows good reproducibility at the 100th demolding cycle.
当零件几何形状从宏观尺度缩小到微观尺度时，尺寸诱导的表面效应在注塑成型过程中变得显著。在此过程中，聚合物与镍（Ni）模具镶件之间的附着力会导致微观结构出现缩颈、翘曲和变形等缺陷。在本研究中，通过在镍表面沉积具有低表面能的自组装单分子层（SAMs）来降低附着力，并进一步提高微观结构的脱模质量。结果表明，通过溶液沉积法可以成功地在镍表面沉积具有化学键和紧密排列的烷基硫醇自组装单分子层。测量了模具镶件表面抗粘附处理前后的接触角、表面自由能和摩擦系数。此外，分析了不同烷基硫醇材料的抗粘附性能以及注塑成型后微观结构零件相应的复制质量。研究发现，经全氟癸硫醇处理的镍模具镶件具有最佳的耐磨性，并且在第100次脱模循环时仍表现出良好的再现性。
