Zou Xin, Chen Ke, Yao Haining, Chen Cong, Lu Xueping, Ding Ping, Wang Min, Hua Xueming, Shan Aidang
School of Materials Science and Engineering, Shanghai Jiao Tong University, No. 800, Dong Chuan Road, Shanghai 200240, P. R. China.
Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, No. 800, Dong Chuan Road, Shanghai 200240, P. R. China.
ACS Appl Mater Interfaces. 2022 Jun 1. doi: 10.1021/acsami.2c04971.
Polymer-metal hybrid structures have attracted significant attention recently due to their advantage of great weight reduction and excellent integrated physical/chemical properties. However, due to great physicochemical differences between polymers and metals, obtaining an interface with high bonding strength is a challenge, which makes it critically important to clarify the underlying bonding mechanisms. In the present research, we focused on revealing the underlying bonding mechanisms of a laminated Cr-coated steel-ethylene acrylic acid (EAA) strip prepared by hot roll bonding from the microscale to the molecular scale with experimental evidence. The microscale mechanical interlocking was analyzed and proven by scanning white light interferometry and scanning electron microscopy (SEM) by means of observing the surface and cross-sectional morphologies. Additionally, interfacial phases and chemical compositions were analyzed by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). More directly and effectively, the interface was successfully exposed for X-ray photoelectron spectroscopy (XPS) analysis. Combined with time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and depth profiling analysis, the formation of -(O═)C-O-Cr and -C-(O-Cr) covalent bonds through chemical reactions at the interface between -COOH and CrO was verified. Based on these characterization results, interfacial bonding mechanisms for the laminated Cr-coated steel-EAA strip were clearly identified to be chemical bonding and micromechanical interlocking, along with hydrogen bonding, which were all demonstrated with solid experimental evidence. In addition, 3D-render view and cross-section images of typical ion fragments at the interface were used to reveal the interfacial structure more comprehensively. The contributions of hydrogen bonds and covalent bonds to the interface were evaluated and compared for the first time. This study provides both methodological and theoretical guidance for investigating and understanding interfacial bonding formation in polymer-metal hybrid structures.
聚合物-金属混合结构因其在大幅减轻重量以及具备优异的综合物理/化学性能方面的优势，近来备受关注。然而，由于聚合物和金属之间存在巨大的物理化学差异，获得具有高结合强度的界面是一项挑战，这使得阐明其潜在的键合机制至关重要。在本研究中，我们专注于通过实验证据从微观尺度到分子尺度揭示通过热轧结合制备的层压镀铬钢-乙烯丙烯酸（EAA）带材的潜在键合机制。通过观察表面和横截面形态，利用扫描白光干涉测量法和扫描电子显微镜（SEM）对微观尺度的机械互锁进行了分析和验证。此外，通过透射电子显微镜（TEM）和能量色散X射线光谱（EDX）对界面相和化学成分进行了分析。更直接有效的是，成功暴露了界面用于X射线光电子能谱（XPS）分析。结合飞行时间二次离子质谱（ToF-SIMS）和深度剖析分析，验证了在-COOH与CrO之间的界面处通过化学反应形成了-(O═)C-O-Cr和-C-(O-Cr)共价键。基于这些表征结果，层压镀铬钢-EAA带材的界面键合机制被明确确定为化学键合、微机械互锁以及氢键，所有这些都有确凿的实验证据证明。此外，还使用了界面处典型离子碎片的三维渲染视图和横截面图像来更全面地揭示界面结构。首次评估并比较了氢键和共价键对界面的贡献。本研究为研究和理解聚合物-金属混合结构中的界面键合形成提供了方法和理论指导。
