CNRS, Centre de Recherche Paul Pascal (CRPP), UPR 8641, F-33600 Pessac, France.
Instituto de Ciencia y Tecnología de Polímeros, CSIC, Juan de la Cierva 3, 28006, Madrid, Spain.
Faraday Discuss. 2017 Jul 1;199:335-347. doi: 10.1039/c6fd00246c. Epub 2017 Apr 28.
The anchoring of polymer chains at solid surfaces is an efficient way to modify interfacial properties like the stability and rheology of colloidal dispersions, lubrication and biocompatibility. Polyelectrolytes are good candidates for the building of smart materials, as the polyion chain conformation can often be tuned by manipulation of different physico-chemical variables. However, achieving efficient and reversible control of this process represents an important technological challenge. In this regard, the application of an external electrical stimulus on polyelectrolytes seems to be a convenient control strategy, for several reasons. First, it is relatively easy to apply an electric field to the material with adequate spatiotemporal control. In addition, in contrast to chemically induced changes, the molecular response to a changing electric field occurs relatively quickly. If the system is properly designed, this response can then be used to control the magnitude of surface properties. In this work we discuss the effect of an external electric field on the adhesion and lubrication properties of several polyelectrolyte-coated surfaces. The influence of the applied field is investigated at different pH and salt conditions, as the polyelectrolyte conformation is sensitive to these variables. We show that it is possible to fine tune friction and adhesion using relatively low applied fields.
聚合物链在固体表面的锚定是一种有效的方法，可以改变胶体分散体的稳定性和流变学、润滑和生物相容性等界面性质。聚电解质是构建智能材料的良好候选物，因为通过操纵不同的物理化学变量，通常可以调整聚离子链构象。然而，实现对该过程的有效和可逆控制是一个重要的技术挑战。在这方面，由于以下几个原因，对外加电刺激在聚电解质上的应用似乎是一种方便的控制策略。首先，相对容易通过适当的时空控制将电场施加到材料上。此外，与化学诱导的变化相比，分子对变化的电场的响应相对较快。如果系统设计得当，这种响应可以用于控制表面性质的大小。在这项工作中，我们讨论了外加电场对几种聚电解质涂层表面的粘附和润滑性质的影响。在不同的 pH 值和盐条件下研究了施加电场的影响，因为聚电解质构象对这些变量很敏感。我们表明，使用相对较低的外加电场可以精细调节摩擦和粘附。
