提出一种关于相变胶囊（EPCMs）的快捷微流控制备方法。通过浸入式共轴流毛细管微流控装置辅以紫外光固化制备C15/TMPTA EPCMs,并添加碳化硅对壳材进行导热改性处理。采用高速摄像机、扫描电子显微镜（SEM）、光学显微镜（OM）、傅里叶红外光谱仪（FT-IR）、X射线衍射仪（XRD）、差式扫描量热仪（DSC）、热重分析仪（TGA）、激光导热仪（LFA）等表征手段探究复合液滴生成和EPCMs性能。结果表明：在所选择的流量参数范围内,复合液滴生成过程存在滴流、核心泄漏和射流3种现象。在滴流和射流现象下,均生成稳定的复合液滴;而当流量比（Qi/Qo）大于1.5、流量之和（Qtotal）小于160 μL/min时,核心液滴会发生泄漏,导致复合液滴无法正常生成。核心液滴及复合液滴尺寸随外相毛细数（Cao）的增大而减小,复合液滴生成频率随Cao的增大而增大。此外,在Qi/Qo为0.5、1.0、1.5,Qtotal为150 μL/min时,制备的EPCMs呈多核结构,具有高单分散性（变异系数（Cv）<4%）,且尺寸可控,粒径为1.32~1.55 mm。添加质量分数为2%的纳米碳化硅进行改性,可提高EPCMs的封装率（提高16.17%）和热循环稳定性,在25次热循环后焓值仅降低1.19%。
Abstract
The paper proposes a rapid microfluidic fabrication method for encapsulated phase change materials （EPCMs）. C15/TMPTA EPCMs are prepared using an immersed co-flowing capillary microfluidic device with UV-curing, supplemented by thermally conductive modification of the shell material with silicon carbide. Characterization techniques including high-speed cameras, SEM, OM, FT-IR, XRD, DSC, TGA and LFA are utilized to investigate the generation of compound droplets and the properties of EPCMs. The results show that within the selected range of flow rate parameters, the generation process of compound droplets exhibits three phenomena： dripping, core leakage and jetting. Under dripping and jetting phenomena, stable compound droplets are formed. However, when the flow rate ratio （Qi/Qo） is larger than 1.5 and the total flow rate （Qtotal） is less than 160 µL/min, the core droplet will leak, resulting in the inability to generate the composite droplet normally. The sizes of core and compound droplets decrease with an increase in the outer phase capillary number （Cao）, while the frequency of compound droplet generation increases with Cao. Moreover, EPCMs prepared at Qi/Qo of 0.5, 1 and 1.5, with a Qtotal of 150 µL/min, exhibit a multi-core structure, high monodispersity （with a coefficient of variation （Cv） <4%） and controllable size, ranging from 1.32 to 1.55 mm in diameter. The addition of 2wt% nano silicon carbide for modification enhances the encapsulation efficiency of EPCMs （increased by 16.17%） and thermal cycling stability, with only a 1.19% decrease in enthalpy value after 25 thermal cycles.
关键词
微流控 /
相变胶囊 /
毛细管 /
液滴生成 /
辐射固化 /
纳米碳化硅
Key words
microfluidics /
phase change capsule /
capillary /
droplet formation /
radiation curing /
nano silicon carbide
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