| 摘要: | 摘要： A ring-shaped stain is frequently left on a substrate by a drying drop containing colloids as a result of contact line pinning and outward flow. In this work, however, different patterns are observed for drying drops containing small solutes or polymers on various hydrophilic substrates. Depending on the surface activity of solutes and the contact angle hysteresis (CAH) of substrates, the pattern of the evaporation stain varies, including a concentrated stain, a ringlike deposit, and a combined structure. For small surface-inactive solutes, the concentrated stain is formed on substrates with weak CAH, for example, copper sulfate solution on silica glass. On the contrary, a ringlike deposit is developed on substrates with strong CAH, for example, a copper sulfate solution on graphite. For surface-active solutes, however, the wetting property can be significantly altered and the ringlike stain is always visible, for example, Brij-35 solution on polycarbonate. For a mixture of surface-active and surface-inactive solutes, a combined pattern of a ringlike and concentrated stain can appear. For various polymer solutions on polycarbonate, similar results are observed. Concentrated stains are formed for weak CAH such as sodium polysulfonate, and ring-shaped patterns are developed for strong CAH such as poly(vinyl pyrrolidone). The stain pattern is actually determined by the competition between the time scales associated with contact line retreat and solute precipitation. The suppression of the coffee-ring effect can thus be acquired by the control of CAH.
其他題名： Langmuir
出版者： Washington, DC: American Chemical Society
出版日期： 2013-06-25
出處： Langmuir, 2013-06, Vol.29 (25), p.7802-7811
資源來源： ACS Publications
版權： Copyright © 2013 American Chemical Society
版權： 2014 INIST-CNRS
識別號： ISSN: 0743-7463
識別號： ISSN: 1520-5827
識別號： EISSN: 1520-5827
識別號： DOI: 10.1021/la400948e
識別號： PMID: 23721254
識別號： CODEN: LANGD5 |
