Probing intermolecular and surface interactions of smart polymers

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Polymers play important roles in numerous engineering and biomedical applications. Many industrial processes and biomedical applications where polymers are involved rely on their fundamental intermolecular and interfacial interactions. Over the past three decades, much effort and significant progress has been made in understanding the adhesion, friction and lubrication of polymers and development of functional polymers. Yet, the quantitative understanding of the intermolecular and surface forces of stimuli-responsive or so-called “smart” polymers, particularly at deformable surfaces (e.g. bubbles, liquid droplets) in complex fluids, is rather limited, which is highly related to many chemical processes and operations in the natural resources industries of Canada (e.g. mineral flotation, bitumen extraction, hydrotransport in oil sands production, tailings water treatment). In this proposed program, a systematic approach will be used to exploit the physicochemical properties and fundamental molecular interaction mechanisms of stimuli-responsive polymers in complex environmental conditions, to elucidate their structure-property correlations at the molecular, nano- and micro-scale. We will use several state-of-the-art and complementary nanomechanical techniques, including surface forces apparatus (SFA), atomic force microscope (AFM) coupled with a special bubble/drop probe technique and reflection interferometry, and a home-built 4-roll mill fluidic device, as the main research tools to: (1) quantify the intermolecular and surface forces (e.g. hydrophobic interactions) of smart polymers at deformable interfaces (e.g. bubbles, liquid droplets), (2) adopt bio-inspired wet adhesion strategies such as DOPA (3, 4-dihydroxyphenyl-L-alanine) chemistry, cation-pi interaction, and stimuli-sensitive function groups to develop novel adhesive polymers and smart self-healing polymers with controllable bulk and surface properties (e.g. adhesion, elasticity, and hydrophobicity), and elucidate their molecular interaction mechanisms and property-structure relationships. The fundamental and quantitative understanding of the properties and molecular interaction mechanisms of these smart polymers will provide significant insights into the design principles and development of more advanced functional materials as well as cutting-edge technologies for better control and effective modulation of many industrial operations (e.g. polymer reaction engineering, ore flotation).