The role of deformability in determining the structural and mechanical properties of bubbles and emulsions
The role of deformability in determining the structural and mechanical properties of bubbles and emulsions
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DOI：
10.1039/c9sm00775j
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发表时间：
2019-08-07
期刊：
影响因子：
3.4
通讯作者：
O'Hern, Corey S.
中科院分区：
文献类型：
--
作者：
Boromand, Arman;Signoriello, Alexandra;O'Hern, Corey S.
我们使用我们为气泡和乳状液开发的具有良好特性的软颗粒(SP)模型和可变形颗粒(DP)模型，对受各向同性压缩的二维堵塞颗粒填充进行了计算研究。在SP模型中，圆形粒子被允许重叠，产生纯粹的排斥力。在DP模型中，粒子将其周长最小化，同时在固定区域变形以避免在压缩过程中重叠。我们比较了用SP和DP模型产生的堵塞填料的结构和力学性能作为填充分数Rho的函数，而不是折合的数密度Phi的函数。结果表明，在大系统极限下，两种模型的超额接触数Delta z=z-z(J)和剪切模量值G均为Delta Rho(0.5)，其中Delta Rho=Rho-Rho(J)和z(J)接近4，Rho(J)接近0.842是干扰开始时的数值。对于大于或类似于0.88的Rho，SP和DP型号的增量z和G开始不同。在这种情况下，类似于G的Delta z可以用Delta Rho中的两个幂定律之和来描述，即类似于G的Delta z类似于C-0 Delta Rho(0.5)+C-1 Delta Rho(1.0)到最低阶。结果表明，DP模型的C-1/C-0比SP模型大得多。我们还刻画了堵塞填料中的空隙空间是Rho的函数。我们发现DP模型可以用Rho-gt；1来描述平台边界的形成。我们进一步表明，DP模型的z和形状因子A与Rho的关系的结果与最近的泡沫和乳状液的实验研究相一致。
pound We perform computational studies of jammed particle packings in two dimensions undergoing isotropic compression using the well-characterized soft particle (SP) model and deformable particle (DP) model that we developed for bubbles and emulsions. In the SP model, circular particles are allowed to overlap, generating purely repulsive forces. In the DP model, particles minimize their perimeter, while deforming at fixed area to avoid overlap during compression. We compare the structural and mechanical properties of jammed packings generated using the SP and DP models as a function of the packing fraction rho, instead of the reduced number density phi. We show that near jamming onset the excess contact number Delta z = z - z(J) and shear modulus G scale as Delta rho(0.5) in the large system limit for both models, where Delta rho = rho - rho(J) and z(J) approximate to 4 and rho(J) approximate to 0.842 are the values at jamming onset. Delta z and G for the SP and DP models begin to differ for rho greater than or similar to 0.88. In this regime, Delta z similar to G can be described by a sum of two power-laws in Delta rho, i.e. Delta z similar to G similar to C-0 Delta rho(0.5) + C-1 Delta rho(1.0) to lowest order. We show that the ratio C-1/C-0 is much larger for the DP model compared to that for the SP model. We also characterize the void space in jammed packings as a function of rho. We find that the DP model can describe the formation of Plateau borders as rho -> 1. We further show that the results for z and the shape factor A versus rho for the DP model agree with recent experimental studies of foams and emulsions.