Carbon Dioxide Stimuli Responsive Polymer Colloids

下一代先进材料将能够通过经历化学或物理性质的变化来应对环境的变化。材料对刺激的反应被称为“触发”，这种材料通常被称为“刺激反应”材料。拟议的研究计划将检查一类新的聚合物纳米颗粒。这些是非常小的颗粒(直径约100纳米，或比人类头发的厚度小1000倍)，可广泛应用于各种产品，其中许多对加拿大具有重要的经济意义，例如包括涂料、密封剂、粘合剂、个人/保健品和化妆品。我们将开发使这些纳米颗粒具有刺激响应性的新方法，以便这些颗粒在接触到触发器后，其性质将经历理想或有益的变化，从而使它们对特定应用更有用或更有价值。众所周知，刺激反应材料的例子包括在强光下变暗的窗户。我们的研究小组最近推出了聚合物纳米颗粒，当暴露在简单、无害的触发剂二氧化碳或空气中时，它们的性质可以发生戏剧性的变化。相比之下，其他现有的刺激响应性聚合物颗粒需要有毒的化学物质，如强酸或强碱来切换。我们只需要将二氧化碳或空气鼓泡到我们的颗粒的水基悬浮液中，就可以改变它们的表面性质，这样颗粒要么以均匀的分散形式存在(在二氧化碳下)，要么作为聚集的粉末存在(在空气中)。这是因为颗粒表面的电荷可以被“切换”。我们将开发三种不同类型的二氧化碳响应性纳米颗粒的制造工艺。一种类型将使用现有产品中常用的现有化学物质，第二种类型将使用一种适用于高级、高附加值应用的新型化学物质，而第三种类型将使用一种从纤维素(加拿大的关键资源)中提取的新型、可切换的可再生纳米材料，称为CNC(晶态纳米纤维素)。进行这项研究的学生将对刺激响应材料和聚合物纳米粒子有广泛的了解，为他们在关键工业部门为加拿大未来的经济发展做出重要贡献做好准备。**

The next generation of advanced materials will be capable of responding to variation in their environment by undergoing changes in their chemical or physical properties. The stimulus to which the materials react is known as a "trigger", and such materials are commonly know as "stimuli-responsive" materials. The proposed research program will examine a new class of polymer nanoparticles. These are very small particles (~100 nm in diameter, or 1000x smaller than the thickness of a human hair) that find application in a wide range of products, many of significant economic importance to Canada, including for example coatings, sealants, adhesives, personal/health care products and cosmetics. We will develop new methods for making these nanoparticles stimuli-responsive, so that the particles will undergo a desirable or beneficial change in their properties upon exposure to a trigger that will make them more useful or valuable for a given application. Well-known examples of stimuli-responsive materials include windows that darken upon exposure to bright light. Our research group recently introduced polymer nanoparticles that can undergo a dramatic change in properties upon exposure to simple, benign triggers; carbon dioxide or air. In contrast, other existing stimuli-responsive polymer particles require toxic chemicals such as strong acids or bases to switch. We only need to bubble carbon dioxide or air into a water-based suspension of our particles to switch their surface properties, so that the particles exist either as a uniform dispersion (under carbon dioxide) or as an aggregated powder (under air). This is achieved because the particle surface electrical charge can be "switched". We will develop processes for making three different types of carbon dioxide responsive nanoparticles. One type will use established chemistry commonly used in existing products, the second type will use a novel chemistry suitable for advanced, high valued-added applications, while the third type will employ a novel, switchable renewable nanomaterial derived from cellulose (a critical resource for Canada), known as CNC (crystalline nanocellulose). Students conducting the research will develop a broad understanding of both stimuli-responsive materials and polymer nanoparticles, preparing them for making important contributions to Canada's future economic development in key industrial sectors.**