液液两相流法制备海藻酸钠包覆的液态金属微滴

本文以室温液态金属(GaInSn)为分散相、海藻酸钠(NaAlg)溶液(1wt%)为连续相,采用液液两相流方法,在竖直共轴微通道中,制备得到NaAlg凝胶包覆的多个GaInSn微滴,具有单分散、尺寸一致的特点。GaInSn/NaAlg两相流存在四种流型:分散相滴流、分散相柱塞流、连续相滴流和连续相射流。GaInSn微滴的包覆模式三种:Squeezing、Dripping和Compound Jetting,其中Dripping和Compound Jetting是主要的包覆模式。在较低的GaInSn流量下,NaAlg流量增加到一定程度后,包覆模式由Dripping转变Compound Jetting。固定两相流量比,随着两相流量的同比例增加,GaInSn微滴的特征频率呈线性增加、包覆个数增加、特征长度变化不显著。

The Microdroplet Preparation of Liquid Metal Encapsulated by the Sodium Alginate with the Method of Liquid-liquid Two-phase Flow

The liquid-liquid two-phase flow method was applied to prepare the liquid metal(GaInSn)microdroplet encapsulated by the sodium alginate.In the vertical coaxial microchannel,the liquid metal(GaInSn)was the dispersed phase and the sodium alginate(NaAlg)solution(1 wt%)was the continuous phase.The NaAlg gel encapsulated the GaInSn microdroplets with the characteristics of monodispersion,uniform size and different numbers.The GaInSn/NaAlg two-phase flow possessed four flow patterns,which were the dripping and squeezing flows in the dispersed phase,and the dripping and jetting flows in the continuous phase.There are three encapsulation modes for GaInSn microdroplet,which were Squeezing,Dripping,and Compound Jetting.The dominant encapsulation modes were Dripping and Compound Jetting.At the low flow rate of GaInSn,the encapsulation mode transferred from Dripping to Compound Jetting responding to the flow rate increasing of NaAlg.With the increase of two flow rates proportionally,the GaInSn microdroplet increased the characteristic frequency and encapsulation number,and changed the characteristic length without significant.