| Summary: | Abstract As an emerging droplet system, monolayer nanoparticle‐covered (mNPc) liquid marbles have shown fascinating properties and application values. Their formation process has been clear, but liquid availability for production has yet to be clarified. This study addresses this issue from the angle of surface tension, revealing critical surface tension and contact angle values for mNPc liquid marble production with both rolling and compression methods. Water‐ethanol and water‐surfactant systems are employed as testing liquids. With irreversible pinning as criterion, critical surface tension values that allow mNPc liquid marble formation are obtained with the two kinds of liquids, forming ranges from 38.6 to 31.8 mN m−1, and from 36.7 to 27.6 mN m−1, for the rolling and compression methods, respectively. Correspondingly, contact angles in the ranges from 132° to 126° and from 116–124° are regarded as the lower limits for mNPc liquid marble production with the rolling and compression methods, respectively. In addition, rupture and deformation behaviors under low surface tension are systematically investigated and a depinning approach that facilitates marble formation is proposed. This study could provide important guidance for various applications that require low surface tension liquids to produce mNPc liquid marbles.
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