| Evaporation-induced nano/micro-particle deposition patterns have broad applications in the fields such as inkjet printing,photonic crystal preparation,functional materials,DNA/RNA mapping and disease diagnosis.However,coffee ring effect and crack in evaporative deposition limit the formation of uniform or ordered evaporative deposition.In this thesis,silicon and flexible materials(polydimethylsiloxane,PDMS)were selected for studying the evaporation of nano/micro-particle suspension droplets on these substrates.The main research contents were as follows:(1)The evaporation of nano/micro particle suspension droplets on silicon and PDMS surfaces was studied.It was found that the evaporation of droplets all started with the constant contact radius(CCR)evaporation mode.In the case of ignoring the influence of nano/micro particle on the evaporation rate and the influence of the substrate on the evaporation of droplets,and assuming that the water vapor concentration gradient was uniform and outward along the radial direction,the theoretical solution of the contact angle in the CCR stage was obtained and compared with the experimental data;(2)The evaporation-induced deposition patterns of nano/micro-particle were studied.On the silicon surface,there were uniform radial cracks with small crack opening displacement;however,on PDMS surfaces,the number of cracks was related to the base-to-curing agent mass ratio of PDMS,and the crack opening displacement was much larger than that in the case of silicon.What’s more,the cause for the difference in crack opening displacement was qualitatively analyzed. |
