Different drying patterns of modified SiO2 nanofluid droplets have been observed and the effects of modified SiO2 nanoparticle deposition layer formed in boiling on pure water boiling heat transfer have also been investigated experimentally. The different drying patterns of nanofluid droplets show that modified function groups can affect whether SiO2 nanoparticles can be adsorbed to the liquid-air interface

and based on this result a conjecture has been made about the effects of modified functional groups on the way of nanoparticle deposition during boiling of nanofluids. From boiling experiments

it is found that polyethylene glycol (PEG) groups modified SiO2 nanoparticles deposition layer on a heater surface can increase average roughness of the heater surface a lot from 160 nm to 977 nm

and it can also increase pure water boiling heat transfer coefficient. However

the sulfonic acid groups modified SiO2 nanoparticles deposition layer on a heater surface affect average roughness of the heater surface a little (increased 60 nm)

and it deteriorates the pure water boiling heat transfer coefficient. The effects of modified functional groups on the deposition of nanoparticles during the boiling process inferred by droplet evaporation experiments were verified by boiling heat transfer experiments.