Construction of Compact Polyelectrolyte Multilayers Inspired by Marine Mussel: Effects of Salt Concentration and pH As Observed by QCM-D and AFM

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• 作者：Weina Wang ; Yisheng Xu ; Sebastian Backes ; Ang Li ; Samantha Micciulla ; A. Basak Kayitmazer ; Li Li ; Xuhong Guo ; Regine von Klitzing
• 刊名：Langmuir
• 出版年：2016
• 出版时间：April 12, 2016
• 年：2016
• 卷：32
• 期：14
• 页码：3365-3374
• 全文大小：727K
• 年卷期：0
• ISSN：1520-5827

文摘

Biomimetic multilayers based on layer-by-layer (LbL) assembly were prepared as functional films with compact structure by incorporating the mussel-inspired catechol cross-linking. Dopamine-modified poly(acrylic acid) (PAADopa) was synthesized as a polyanion to offer electrostatic interaction with the prelayer polyethylenimine (PEI) and consecutively cross-linked by zinc to generate compact multilayers with tunable physicochemical properties. In situ layer-by-layer growth and cross-linking were monitored by a quartz crystal microbalance with dissipation (QCM-D) to reveal the kinetics of the process and the influence of Dopa chemistry. Addition of Dopa enhanced the mass adsorption and led to the formation of a more compact structure. An increase of ionic strength induced an increase in mass adsorption in the Dopa-cross-linked multilayers. This is a universal approach for coating of various surfaces such as Au, SiO₂, Ti, and Al₂O₃. Roughness observed by AFM in both wet and dry conditions was compared to confirm the compact morphology of Dopa-cross-linked multilayers. Because of the pH sensitivity of Dopa moiety, metal-chelated Dopa groups can be turned into softer structure at higher pH as revealed by reduction of Young’s modulus determined by MFP-3D AFM. A deeper insight into the growth and mechanical properties of Dopa-cross-linked polyelectrolyte multilayers was addressed in the present study. This allows a better control of these systems for bioapplications.