Assembly of nanoparticles at the contact line of a drying droplet under the influence of a dipped tip

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• 作者：Kemal Keseroğ ; lu^a ; Mustafa Ç ; ulha ; ^a ; ^{mculha@yeditepe.edu.tr"" rel=""nofollow} ; ^{mculha1@gmail.com"" rel=""nofollow}
• 关键词：Nanoparticles ; Droplet ; Contact line pinning ; Self-assembly
• 刊名：Journal of Colloid and Interface Science
• 出版年：2011
• 出版时间：1 August 2011
• 年：2011
• 卷：360
• 期：1
• 页码：8-14
• 全文大小：1548 K

文摘

The manipulation of colloidal nanoparticles (NPs) in a drying droplet has critical importance not only for several industrial applications but also their assembly into patterns on surfaces. The influence of a tip with hydrophilic or hydrophobic surfaces dipped into a drying droplet on hydrophilic or hydrophobic surfaces on the behavior of 98 nm latex NPs was investigated. The formation of concentric rings on hydrophilic glass surfaces regardless of the surface chemistry of the dipped tip was observed. On the other hand, no pattern formation on hydrophobic surfaces was observed with the insertion of the tip. With a hydrophilic tip, the concentric rings were formed due to stick–slip motion of the solvent contact line resulting from competition between pinning and capillary forces while the capillary effect was not effective until the surface of the tip was changed by adherent NPs making the tip surface available for water adherence with a hydrophobic tip, which results in the pulling of droplet towards the tip. It is also found that the tip thickness and suspension concentration significantly influences the formation of concentric rings on surfaces. This simple procedure can be used to influence the distribution or assembly of NPs in the droplet area.