Nanoemulsions are widely used in applications such as food products, cosmetics, pharmaceuticals, and enhanced oil recovery for which the ability to engineer material properties is desirable. Moreover, nanoemulsions are emergent model colloidal systems because of the ease in synthesizing monodisperse samples, flexibility in formulations, and tunable material properties. In this work, we study a nanoemulsion system previously developed by our group in which gelation occurs through thermally induced polymer bridging of droplets. We show here that the same system can undergo a sol–gel transition at room temperature through the addition of salt, which screens the electrostatic interaction and allows the system to assemble via depletion attraction. We systematically study how the addition of salt followed by a temperature jump can influence the resulting microstructures and rheological properties of the nanoemulsion system. We show that the salt-induced gel at room temperature can dramatically restructure when the temperature is suddenly increased and achieves a different gelled state. Our results offer a route to control the material properties of an attractive colloidal system by carefully tuning the interparticle potentials and sequentially triggering the colloidal self-assembly. The control and understanding of the material properties can be used for designing hierarchically structured hydrogels and complex colloid-based materials for advanced applications.

中文翻译：

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通过顺序筛选静电排斥，然后热诱导液滴桥接，调节纳米乳液的材料性能。

纳米乳液被广泛用于诸如食品，化妆品，药​​物和提高油采收率的应用中，对于这些应用而言，需要能够对材料特性进行工程设计的能力。此外，由于易于合成单分散样品，配方的灵活性以及可调节的材料特性，纳米乳液是新兴的胶体体系。在这项工作中，我们研究了由我们小组先前开发的一种纳米乳液系统，其中通过热诱导液滴的聚合物桥接发生胶凝。我们在这里表明，同一系统在室温下可以通过添加盐进行溶胶-凝胶转变，这可以屏蔽静电相互作用，并允许系统通过耗竭吸引进行组装。我们系统地研究了盐的添加以及温度跃迁如何影响纳米乳液体系的最终微观结构和流变性。我们显示，当温度突然升高并达到不同的胶凝状态时，室温下的盐诱导凝胶可以显着重组。我们的结果提供了一种通过仔细调节粒子间电势并顺序触发胶体自组装来控制有吸引力的胶体系统的材料特性的途径。对材料特性的控制和理解可用于设计分层结构的水凝胶和复杂的基于胶体的材料，以用于高级应用。我们显示，当温度突然升高并达到不同的胶凝状态时，室温下的盐诱导凝胶可以显着重组。我们的结果提供了一种通过仔细调节粒子间电势并顺序触发胶体自组装来控制有吸引力的胶体系统的材料特性的途径。对材料特性的控制和理解可用于设计分层结构的水凝胶和复杂的基于胶体的材料，以用于高级应用。我们表明，当温度突然升高并达到不同的胶凝状态时，室温下的盐诱导凝胶可以显着重组。我们的结果提供了一种通过仔细调节粒子间电势并顺序触发胶体自组装来控制有吸引力的胶体系统的材料特性的途径。对材料特性的控制和理解可用于设计分层结构的水凝胶和复杂的基于胶体的材料，以用于高级应用。