Nakayama Yasuya
Department of Chemical Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan.
Polymers (Basel). 2023 Dec 26;16(1):77. doi: 10.3390/polym16010077.
Interfaces in soft materials often exhibit deviation from non-slip/stick response and play a determining role in the rheological response of the overall system. We discuss detection techniques for the excess interface rheology using small-amplitude oscillatory shear (SAOS) measurements. A stacked bilayer of different polymers is sheared parallel to the interface and the dynamic shear response is measured. Deviation of the bilayer shear modulus from the superposition of the shear moduli of the component layers is analysed. Furthermore, we introduce a frequency-dependent non-stick length based on the bilayer SAOS response to characterize the excess interface rheology. We observe an approximate stick response in the interface in bilayers composed of the chemically same monomer as well as an apparent slip in the interface between immiscible polymers. The results suggest that the proposed non-stick length in SAOS is capable of detecting the apparent interfacial slip. The non-stick length in SAOS is readily applicable to other complex interfaces of different soft materials and offers a convenient tool to characterize the excess interface rheology.
软材料中的界面通常表现出偏离非滑移/粘附响应的特性，并在整个系统的流变响应中起决定性作用。我们讨论了使用小振幅振荡剪切（SAOS）测量来检测过量界面流变学的技术。将不同聚合物的堆叠双层沿平行于界面的方向进行剪切，并测量动态剪切响应。分析双层剪切模量与各组分层剪切模量叠加值的偏差。此外，我们基于双层SAOS响应引入了一个频率相关的非粘附长度，以表征过量界面流变学。我们观察到，由化学性质相同的单体组成的双层中的界面呈现出近似的粘附响应，而不相容聚合物之间的界面则出现明显的滑移。结果表明，SAOS中提出的非粘附长度能够检测到明显的界面滑移。SAOS中的非粘附长度很容易应用于其他不同软材料的复杂界面，并为表征过量界面流变学提供了一种便捷的工具。
