Temperature dependent mechanical properties of air, oil and water filled microcapsules studied by atomic force microscopy

Abstract

We measured the mechanical properties of air and oil(tetradecane)filled cross-linked lysozyme as well as water filled metal phenolate microcapsules using atomic force microscopy in the temperature range of 21–70 °C. The stiffness and modulus of the individual capsules were determined using Reissner's theory for indentation of thin elastic shells. We found that the stiffness and modulus of air filled cross-linked lysozyme capsules decreases by a factor of 4 when the temperature changes from room temperature to human body temperature of 37 °C. However, the stiffness of tetradecane filled cross-linked lysozyme microcapsules decreases by 16% for the same change in the temperature. The stiffness ..