Versatile modification of surfaces using scalable gas-phase chemical reactions

在过去的十年中，纳米颗粒的尺寸和表面驱动特性吸引了大量的研究兴趣。事实上，纳米颗粒足够小，它们可以掺入其他介质中以带来新的特性（增强的强度、更好的传热和导电性、光吸收等）。而不显著影响主介质的现有性质（重量或粘度增加、柔韧性等）。- 这些被称为纳米复合材料。此外，由于其尺寸小，纳米颗粒也正在生物医学领域进行研究：它们小到足以穿过某些细胞膜，因此可以作为药物载体。然而，在这些应用中使用纳米颗粒需要一个共同的步骤：它们的表面必须经过预处理。事实上，它们的高表面积与体积比使得颗粒团聚成为显著的公害-未经处理的纳米颗粒倾向于团聚并形成不具有所需“纳米”性质的较重结构。除了防止团聚之外，处理步骤还可以用于将额外的功能接枝到纳米颗粒的表面，从而为更多的应用铺平道路。虽然以前的研究已经成功地使用表面活性剂或基于液体的功能化方法预处理纳米颗粒，但这些方法现在面临严重的限制。表面活性剂在纳米复合材料加工中通常遇到的小的热负荷下解吸。虽然官能化在这一领域表现更好，但基于液体的方法面临着它们自己的问题：溶剂相容性、复杂反应、毒性和难以将官能化颗粒与剩余试剂和/或副产物分离（当试图形成多功能表面时，这些问题变得复杂）。因此，本研究计划将重点关注不受这些限制的更通用的气相纳米颗粒功能化方法。具体而言，光引发的CVD将是优选的功能化工具，因为它在定制颗粒表面方面显示出前景。这项工作预计将扩大我们的功能化和定制纳米粒子的能力，并将对加拿大先进材料行业产生重大影响。

The size- and surface-driven properties of nanoparticles have attracted a great deal of research interest in the past decade. Indeed, nanoparticles are sufficiently small that they may be incorporated into other media to bring about new properties (enhanced strength, better heat transfer and electrical conductivity, optical absorbance, etc.) without significantly affecting the existing properties of the host media (weight or viscosity increase, flexibility, etc.) - these are called nanocomposites. Moreover, because of their small size, nanoparticles are also being studied in the field of biomedicine: they are small enough to cross certain cellular membranes and can thus act as drug carriers. However, there is one common step required to use nanoparticles in any of these applications: their surface must be pre-conditioned. Indeed, their high surface-to-volume ratio makes particle agglomeration a significant nuisance - untreated nanoparticles tend to agglomerate and form heavier structures that do not possess the desired "nano" properties. Beyond preventing agglomeration, the treatment step can be used to graft additional functionalities to the nanoparticle's surface, thus paving the way for more applications. While previous studies have successfully pre-conditioned nanoparticles using surfactants or liquid-based functionalization methods, these are now facing severe limitations. Surfactants desorb under the small heat loads commonly encountered in nanocomposite processing. While functionalization fares better in this area, the liquid-based approaches face their own share of issues: solvent compatibility, complex reactions, toxicity and difficulty in separating the functionalized particles from leftover reagents and/or by-products (issues that are compounded when attempting to form multifunctional surfaces). As such, the present research program will focus on more versatile gas-phase nanoparticle functionalization methods that are not subject to these limitations. Specifically, photo-initiated CVD will be the preferred functionalization tool, as it shows promise in tailoring particle surfaces. This work is expected to extend our capabilities to functionalize and tailor nanoparticles and will have a strong impact on the Canadian advanced materials sector.