Microdroplet dissolution into a second-phase solvent using a micropipet technique: Test of the Epstein-Plesset model for an aniline-water system
Microdroplet dissolution into a second-phase solvent using a micropipet technique: Test of the Epstein-Plesset model for an aniline-water system
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DOI：
10.1021/la053314e
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发表时间：
2006-04-25
期刊：
影响因子：
3.9
通讯作者：
Needham, D
中科院分区：
文献类型：
--
作者：
Duncan, PB;Needham, D
Epstein-Plesset模型最初是为单个气泡在无限大的水溶液中的溶解而推导的(Epstein，P.S.；Plesset，M.S.J.Chem)。太棒了。1950、18年、1505-1509年)。微管操作技术以前被证明可以在空气微泡和充气的脂质涂层微粒上准确和适当地测试这一理论(Duncan，P.B.；Needham，D.Langmuir 2004，20,2567-2578)。这一同样的理论现在被用来模拟液体微滴在明确定义的溶液环境中的溶解。如前所述，对于气泡系统，在微管末端保持单个微粒不会影响溶解分布，并允许显著的各向同性扩散，这是验证该理论的必要条件。本文采用初始液滴直径为50微米的苯胺-水体系作为液液体系的模型。测试了用不同浓度的苯胺预饱和的水溶液中的微滴苯胺，以及水滴在苯胺溶液中的反系统。根据Epstein-Plesset时间依赖理论(包括建立固定层所需的时间)，忽略界面张力，溶解寿命随介质饱和度的增加而增加。通过将饱和分数从0增加到0.9，液滴寿命可以增加一个数量级(从大约10个数量级增加到100个S)，如果从0.9增加到0.99，则可以增加另一个数量级。该技术是一种准确、合适的测试单个液体微滴在第二种液体溶液中溶解的方法，并为研究聚合物和其他微粒的形成建立了一套系统的实验和理论方法。
The Epstein-Plesset model was originally derived for the dissolution of a single gas bubble in an infinite aqueous solution (Epstein, P. S.; Plesset, M. S. J. Chem. Phys. 1950, 18, 1505-1509). The micropipet manipulation technique was previously shown to test this theory on air microbubbles and air-filled lipid-coated microparticles accurately and appropriately (Duncan, P. B.; Needham, D. Langmuir 2004,20,2567-2578). This same theory is now tested to model liquid microdroplet dissolution in a well-defined solution environment. As presented previously for the gas-bubble system, holding a single microparticle at the end of a micropipet was not shown to affect the dissolution profile and allowed isotropic diffusion significantly, a necessary condition for the validation of the theory. Here, an aniline-water system with an initial droplet diameter of 50 mu m was used as a model liquid-liquid system. A microdroplet of aniline in an aqueous solution presatureated with aniline at distinct levels was tested, as was the reverse system of a water droplet in an aniline solution. The dissolution lifetime was shown to increase with increasing medium saturation fraction according to the Epstein-Plesset time-dependent theory (including the time required to establish the stationary layer) neglecting interfacial tension. The droplet lifetime can be increased by an order of magnitude (from about 10 to 100 s) by increasing the saturation fraction from 0 to 0.9 and by another order of magnitude by increasing from 0.9 to 0.99. The technique proved to be an accurate and appropriate method to test the dissolution of single liquid microdroplets in a second liquid solution and establishes a systematic experimental and theoretical approach to the investigation of the formation of polymer and other microparticles.