微封装制造中胶液分配体积计算与预测研究

针对针转移式皮升分辨率超微量胶液分配方法,研究胶液分配初始距离对胶滴体积的影响,建立了基于初始距离量化分配形成微小液滴体积大小的公式。利用像素法对实验胶滴样本图像进行分析并确定出胶滴真实体积大小,并基于实验分析结果利用数值拟合方法建立胶滴体积的数学量化方法;最后,将量化方法与胶滴数学体积模型进行对比分析。根据实验所得数据,推导出了通过初始距离对胶滴体积预测的数学公式。实验结果表明:预测体积、预测接触面积与实际值之间的平均差异率分别为0.47%和0.54%。根据实际工作情况,对胶滴相应参数进行研究与预测,不但可以对胶滴相关配置参数进行精确调整,而且可以对实际封装效果进行初步判断,从而提高封装效率及准确性。

Pattern transition and sluggish cracking of colloidal droplet deposition with polymer additives

Drying of colloidal droplets often develops versatile depositions.We study the drying deposition of both colloidal droplets containing silica nanoparticles and the silica colloidal droplets with polyethylene oxide(PEO) additives.We focus on the effect of polymer additives on the deposition formation and the cracking dynamics by using in-situ microscope observation.With PEO additives,a transition from ring-like deposition to uniform deposition is observed,and the cracking dynamics is greatly reduced.The PEO additives enhance the adsorption of particles at the air-water interface,thus forming the network structure at the interface which blocks the outward capillary flow.This contributes to the uniform deposition.Meanwhile,the multi-distribution of the aggregates size enhances the non-homogeneity of the drying film and consequently results in multi-nucleation of cracks.This reduces the stress accumulation that drives the crack propagation and may be responsible for the sluggish cracking dynamics.