“Coffee ring effects” is one of notable non-equilibrium processes in thermodynamics. Nonetheless, this study has heavily relied upon conventional imaging technologies such as visible light or fluorescent microscopy. In this work, we studied the drying, and precipitation processes of model proteins (Bovine Serum Albumin, γ-Globulin and Fibrinogen) by utilizing FT-IR imaging technology, and we report the real-time observation of coffee ring formation, presenting the different kinetic profiles for the three samples on hydrophobic and hydrophilic surfaces. The analysis of two and three component mixtures also allow to observe the segregation of globular proteins in different layers of the ring. To provide account for the discovery, we established a straight-forward, thermodynamic model to interpret protein transport in an evaporating droplet of medium.

Protein mixture segregation at coffee ring: Real-time imaging of protein ring precipitation by mid-FTIR spectromicroscopy

253rd National Meeting (2017)

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