论文标题
通过胶体振荡受控的凝胶膨胀
Controlled gel expansion through colloid oscillation
论文作者
论文摘要
我们对嵌入在交联聚合物凝胶中的单个胶体的行为进行建模，并浸入粘性背景流体中。外场将粒子驱动到周期性运动中，该运动变形了嵌入矩阵并创建局部微腔，其中包含粒子和其运动产生的任何自由体积。该空腔仅在粒子被驱动时就存在，并且在存在时会降低材料的局部密度，从而导致肿胀。我们表明该模型具有丰富的共振特征，但总体上以低驾驶频率和高驱动频率的清晰缩放定律为特征，并且在中间频率下具有明显的共振。我们的模型预测表明，通过改变材料的弹性模量或交联密度，可以改变共振的大小和位置，而局部粘度主要具有阻尼效果。我们的工作表明，即使在简单的叠加近似值的水平上，也可以将胶体的集合分散在培养基中，这可能是可以产生明显的自由体积生成。
We model the behaviour of a single colloid embedded in a cross-linked polymer gel, immersed in a viscous background fluid. External fields actuate the particle into a periodic motion, which deforms the embedding matrix and creates a local micro-cavity, containing the particle and any free volume created by its motion. This cavity exists only as long as the particle is actuated and, when present, reduces the local density of the material, leading to swelling. We show that the model exhibits rich resonance features, but is overall characterised by clear scaling laws at low and high driving frequencies, and a pronounced resonance at intermediate frequencies. Our model predictions suggest that both the magnitude and position of the resonance can be varied by varying the material's elastic modulus or cross-linking density, whereas the local viscosity primarily has a dampening effect. Our work implies appreciable free-volume generation is possible by dispersing a collection of colloids in the medium, even at the level of a simple superposition approximation.
