Depletion forces between particles immersed in nanofluids

• Nanofluids may contain soft, self-assembled nanostructures of different size, shape and surface chemistry.
• Phase transitions in binary colloidal mixtures with large size and geometry asymmetry can offer relevant insights.
• Direct measurement of depletion and structural forces in nanofluids is limited.
• The role of proteo-nanofluids mediated depletion in cellular organisation and biological processes is under-appreciated.
• Many theoretical and experimental challenges and opportunities remain.

Understanding depletion forces between colloidal particles mediated by nanofluids, i.e. liquids containing hard or soft nanostructures, is immensely important in a number of industrial processes. We anticipate added complexities due to enhanced and multifactorial inter-depletant interactions associated with their size, shape, surface chemistry, and concentration. Here we briefly review recent efforts in direct measurement of depletion forces mediated by nanofluids, as well as a number of related studies on the phase transition in binary colloid mixtures with large size and shape asymmetry, a process in which depletion forces play an important role. We will also discuss the often under-appreciated importance of depletion forces mediated by proteo-nanofluids (liquids containing proteins) in facilitating cellular organisation. Some challenges and outstanding questions will emerge from the above discussions, as briefly summarised.

Figure optionsDownload high-quality image (230 K)Download as PowerPoint slide