Probing and Modulating Interactions of Drops, Bubbles and Particles with Implications for Chemical Engineering Processes

加拿大拥有丰富的自然资源（例如，矿产、原油、原油沥青、天然气），为国民经济做出了重大贡献。液滴、气泡和固体颗粒在复杂流体环境中的相互作用，特别是在存在界面活性物质（例如，表面活性剂、聚合物、颗粒），在确定自然资源生产中的许多工程过程的效率和性能方面起着关键作用（例如，矿物浮选、沥青提取、油/水分离、废水处理）。以前的研究主要集中在软材料和颗粒系统的分子间和表面相互作用与“干净”的界面（没有界面活性物种）和均匀的表面化学固体基板。然而，在实际工程应用中，界面活性物种广泛存在于固体/油/水/气界面和体相流体中，而许多固体表面显示出表面化学的不均匀性。量化这些可变形材料系统的相互作用力（例如，液滴、气泡）和在界面活性物质存在下具有表面异质性的固体更具挑战性，但具有基本和实际重要性，这将是本研究的主要焦点。该计划的长期目标是阐明在界面活性物质（例如，表面活性剂、聚合物、纳米颗粒）。短期目标是（1）在界面活性物质存在下，通过调节表面化学、纳米级异质性、界面分子流动性和水化学，量化分子间和表面力，并建立水介质中液滴、气泡和固体颗粒的相互作用机制，特别是疏水相互作用，以及（2）阐明液滴的相互作用机制，气泡和具有光滑表面的固体颗粒，朝向具有液滴/气泡/颗粒的受控运动操纵的新型光滑表面的发展。拟议的研究将填补在界面活性物质存在下的液滴，气泡和精细固体的基本相互作用机制的知识空白，特别是关于其分子间和表面力的量化，疏水相互作用的起源，以及疏水效应和其他表面力如何有助于它们的相互作用行为（例如，组装、聚集和聚结）。拟议的研究还将为如何有效地调节相关工程过程中的这些相互作用提供新的见解，并帮助开发新材料和表面，以实现更高效的工业过程。研究成果将促进自然资源的可持续发展。

Canada has a vast wealth of natural resources (e.g., minerals, crude oil, crude bitumen, natural gas), contributing significantly to the national economy. The interactions of liquid drops, gas bubbles and solid particles in complex fluid environment, particularly in the presence interface-active species (e.g., surfactants, polymers, particles), play a critical role in determine the efficiency and performance of numerous engineering processes in natural resources production (e.g., mineral flotation, bitumen extraction, oil/water separation, wastewater treatment). Previous studies have mainly focused on the intermolecular and surface interactions of soft materials and particle systems with "clean" interfaces (without interface-active species) and solid substrates with homogeneous surface chemistry. In practical engineering applications, however, interface-active species are widely present at solid/oil/water/gas interfaces and in bulk fluids, while many solid surfaces show heterogeneity in surface chemistry. Quantifying the interaction forces of these deformable material systems (e.g., drops, bubbles) and solids with surface heterogeneity in the presence of interface-active species is much more challenging, but is of fundamental and practical importance, which will be the main focus of this proposed research. The long-term objective of this proposed program is to elucidate the physicochemical properties and interaction mechanisms of drops, bubbles and particles in the presence of interface-active species (e.g., surfactants, polymers, nanoparticles) at the nano- and micro-scale. The short-term objectives are to (1) quantify the intermolecular and surface forces and establish the interaction mechanisms, particularly hydrophobic interaction, of liquid drops, gas bubbles and solid particles in aqueous media, by modulating surface chemistry, nanoscale heterogeneity, interfacial molecular mobility and water chemistry, in the presence of interface-active species, and (2) elucidate the interaction mechanisms of liquid drops, gas bubbles and solid particles with slippery surfaces, towards the development of novel slippery surfaces with controlled motion manipulation of drops/bubbles/particles. The proposed research will fill the knowledge gap on the fundamental interaction mechanisms of drops, bubbles and fine solids in the presence of interface-active species, particularly on quantification of their intermolecular and surface forces, the origin of hydrophobic interactions, and how hydrophobic effects and other surface forces contribute to their interaction behaviors (e.g., assembly, aggregation, and coalescence). The proposed research will also provide new insights on how to efficiently and effectively modulate these interactions in related engineering processes and help develop new materials and surfaces towards more efficient industrial processes. The research outcomes will facilitate the sustainable development of natural resources.