Influence of n-octanol and α-terpineol on thin film stability and bubble attachment to hydrophobic surface.
Influence of n-octanol and α-terpineol on thin film stability and bubble attachment to hydrophobic surface.
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DOI：
10.1039/c2cp43545d
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发表时间：
2013-01
期刊：
影响因子：
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通讯作者：
D. Kosior;J. Zawała;M. Krasowska;K. Małysa
中科院分区：
文献类型：
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作者：
D. Kosior;J. Zawała;M. Krasowska;K. Małysa
我们已经研究了通常用作浮选起泡剂的表面活性剂（α-松油醇和正辛醇）的浓度和固体表面的粗糙度对上升气泡与模型疏水Teflon表面碰撞期间发生的现象的影响。使用以1040 Hz频率工作的高速照相机测定在碰撞气泡和Teflon表面之间形成的膜的三相接触（TPC）形成时间（t（TPC））和排水时间（t（D））。Teflon表面粗糙度在微观尺度上变化，粗糙度范围为1 - 100 μm。我们已经发现，在不存在和存在的表面活性剂的情况下，特氟龙表面的粗糙度是TPC形成的动力学的关键因素。随着表面粗糙度的增加，1 ~ 80 μm时，t（TPC）可以缩短一个数量级，即从105 ms缩短到几毫秒。我们已经证明，碰撞气泡的反弹是负责TPC形成的时间在不同粗糙度的聚四氟乙烯表面的巨大差异。低浓度的α-松油醇和正辛醇导致相对于蒸馏水的t（TPC）降低。然而，在高浓度下，t（TPC）延长。TPC形成的时间的延长取决于Teflon表面粗糙度，我们将这种效果归因于不同粗糙度的疏水表面的空腔和划痕中存在的不同量的空气。提出了在高浓度表面活性物质（起泡剂过量）下t（TPC）延长的机理。
We have investigated the influence of concentration of surfactants typically used as flotation frothers (α-terpineol and n-octanol) and roughness of the solid surface on phenomena occurring during rising bubble collisions with a model hydrophobic Teflon surface. The time of three-phase contact (TPC) formation (t(TPC)) and the time of drainage (t(D)) of the film formed between the colliding bubble and Teflon surfaces were determined using a high-speed camera working with a frequency 1040 Hz. The Teflon surface roughness was varied on a microscopic scale, within a roughness ranging between 1 and 100 μm. We have found that the roughness of the Teflon surface is a crucial factor of the kinetics of the TPC formation, both in the absence and in the presence of the surfactants. With the surface roughness increasing from ca. 1 to 80 μm the t(TPC) can be shortened by an order of magnitude, i.e. from 105 ms down to a few milliseconds. We have demonstrated that bouncing of the colliding bubble is responsible for the large differences in the times of TPC formation at the Teflon surfaces of different roughness. Low concentrations of α-terpineol and n-octanol caused a decrease in the t(TPC) with respect to distilled water. However, at high concentrations the t(TPC) was prolonged. The prolongation of the time of the TPC formation was dependent on the Teflon surface roughness and we have attributed this effect to different amounts of air present in the cavities and scratches of hydrophobic surfaces of different roughness. The mechanism of prolongation of the t(TPC) at high concentration of surface-active substances (frother overdosage) is proposed.