Carbon Dioxide Stimuli Responsive Polymer Colloids

下一代先进材料将能够通过改变其化学或物理性质来应对环境的变化。材料对其反应的刺激被称为“触发器”，并且此类材料通常被称为“刺激响应”材料。拟议的研究计划将研究一类新的聚合物纳米颗粒。这些是非常小的颗粒（直径约100 nm，或比人类头发厚度小1000倍），可用于广泛的产品，其中许多对加拿大具有重要的经济意义，包括例如涂料，密封剂，粘合剂，个人/保健产品和化妆品。我们将开发新的方法，使这些纳米粒子刺激响应，使粒子将经历一个理想的或有益的变化，其性质暴露于触发器，这将使他们更有用或有价值的特定应用程序。刺激响应材料的众所周知的例子包括在暴露于强光时变暗的窗户。我们的研究小组最近引入了聚合物纳米颗粒，这些纳米颗粒在暴露于简单、良性的触发物（二氧化碳或空气）时，性质会发生巨大变化。相比之下，其他现有的刺激响应性聚合物颗粒需要有毒化学物质如强酸或强碱来转换。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，以改变它们的表面性质，这样颗粒就可以以均匀的分散体（在二氧化碳下）或聚集的粉末（在空气下）存在。这是因为颗粒表面电荷可以“切换”。我们将开发制造三种不同类型的二氧化碳响应纳米颗粒的工艺。一种类型将使用现有产品中常用的化学物质，第二种类型将使用适用于先进的高附加值应用的新型化学物质，而第三种类型将使用一种新型的可转换的可再生纳米材料，该材料来源于纤维素（加拿大的关键资源），称为CNC（结晶纳米纤维素）。进行研究的学生将对刺激响应材料和聚合物纳米颗粒有广泛的了解，为加拿大未来在关键工业领域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.**