Solid-state NMR studies of polymers, liquid crystals and surfactants at surfaces and interfaces

聚合物、液晶和表面活性剂表面和界面的固态核磁共振研究

• 批准号: 138271-2007
• 负责人: Reven, Linda
• 金额: $ 5.06万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=365097
• 关键词: Solid; state; NMR; studies; polymers

The major theme of my research is NMR studies of the dynamic and structural properties of small molecules and polymers at surfaces and interfaces. Main projects include 1) organic monolayers  2) polyelectrolyte multilayers and 3) nanoparticle/ liquid crystal composites. A large range of surface and colloidal characterization techniques are used in conjunction with solids NMR  such as surface infrared spectroscopy, light scattering,  optical microscopy, calorimetry and electrophoresis. Previous work on organic monolayers established the surface bonding  and chain dynamics of simple alkane monolayers. The next stage will focus on the binding of other molecules and macromolecules to these monolayers. Polyelectrolytes are highly charged polymers. The basic structural and dynamic properties of polyelectrolyte multilayers consisting of stong/strong and strong/weak polyanion/polycation combinations deposited on colloidal substrates have been explored by solids NMR. We will now move onto multilayers based on hydrogen bonding, deposited on nanoparticles and as hollow capsules. One goal is to understand the response of the capsules (shrinking versus swelling) to temperature, pH or salt which is relevant to their use as drug delivery agents. Our initial work on liquid crystals has focused on the "memory effect" of nanoparticle silica filled liquid crystals which have applications in display devices. These materials are initially opaque but become optically transparent in an electric field. This state persists after the field is turned off due to the formation of an ordered silica network. How such networks form is poorly understood. Wideline deuterium NMR is an excellent method for analyzing such structures. We will also study liquid crystal/ metal nanoparticle composites. The goal will be to create an ordered array so that the optical properties can be tuned by an applied field. Solids NMR will again provide a sensitive probe of the  the alignment of the liquid crystal molecules at the particle surfaces.

我研究的主要主题是表面和界面上小分子和聚合物的动态和结构特性的核磁共振研究。主要研究方向：1)有机单层膜；2)聚电解质多层膜；3)纳米颗粒/液晶复合材料。大范围的表面和胶体表征技术与固体核磁共振结合使用，如表面红外光谱，光散射，光学显微镜，量热法和电泳。先前对有机单层的研究建立了简单烷烃单层的表面键合和链动力学。下一阶段将专注于其他分子和大分子与这些单层的结合。聚电解质是高度带电的聚合物。利用固体核磁共振研究了由强/强和强/弱聚阴离子/多阳离子组合组成的聚电解质多层膜的基本结构和动力学性质。我们现在将转向基于氢键的多层材料，沉积在纳米颗粒上，形成空心胶囊。一个目标是了解胶囊对温度、pH值或盐的反应（收缩与膨胀），这与它们作为药物递送剂的使用有关。我们对液晶的初步研究主要集中在纳米二氧化硅填充液晶的“记忆效应”上，这些液晶在显示设备中有应用。这些材料最初是不透明的，但在电场中变得透明。由于有序二氧化硅网络的形成，这种状态在电场关闭后仍然存在。人们对这种网络是如何形成的知之甚少。宽线氘核磁共振是分析这类结构的一种很好的方法。我们还将研究液晶/金属纳米颗粒复合材料。我们的目标是创建一个有序的数组，这样光学特性就可以通过应用字段来调整。固体核磁共振将再次提供一个敏感的探针液晶分子在颗粒表面的排列。