A simple feature of yielding behavior of highly dense suspensions of soft micro-hydrogel particles.
A simple feature of yielding behavior of highly dense suspensions of soft micro-hydrogel particles.
复制标题
软微水凝胶颗粒高密度悬浮液屈服行为的简单特征。
作者：
K. Urayama;Taku Saeki;Shengquan Cong;Shota Uratani;T. Takigawa;Masaki Murai;D. Suzuki
具有窄尺寸分布（典型地，μ eff > 0.9，其中μ eff是颗粒的表观体积分数）的软微水凝胶的高密度悬浮液形成规则的晶格结构，在屈服行为中表现出简单的特征：屈服应变γc [ca. 2.5%左右。聚（N-异丙基甲基丙烯酰胺）（PNIPMA）和聚（N-异丙基丙烯酰胺）（PNIPA）水凝胶颗粒的γ c分别为4.8%]在本文研究的有限c范围内对交联浓度（cx）、颗粒直径（Dh）和颗粒浓度（c）几乎不敏感，并且γc在两个数量级以上的宽范围平衡剪切模量内几乎恒定。此外，在由单分散和双分散微凝胶分别形成的具有结晶和玻璃态结构的致密浆料中，没有观察到明显的γc差异。这与Koumakis等人[Soft Matter，4，2008（2008）]报道的由硬球形成的晶体和玻璃的γc的有限差异形成对比。此外，NIPA核-NIPMA壳微凝胶的高密度悬浮液的γc与NIPMA微凝胶的γc相似。这些结果表明，高密度悬浮液的软微水凝胶的γc主要取决于颗粒表面附近的组成聚合物的种类。预期屈服应变γc受短程相互作用（如粘附和摩擦）控制。
The highly dense suspensions of soft micro-hydrogels with a narrow size distribution (typically ϕeff > 0.9 where ϕeff is the apparent volume fraction of the particle), which form a regular lattice structure, exhibit a simple feature in the yielding behavior: the yield strain γc [ca. 2.5% and ca. 4.8% for poly(N-isopropylmethacrylamide) (PNIPMA) and poly(N-isopropylacrylamide) (PNIPA) hydrogel particles, respectively] is nearly insensitive to the cross-link concentration (cx), particle diameter (Dh), and particle concentration (c) in the limited c range examined here, and γc is almost constant in a wide range of equilibrium shear moduli over two orders of magnitude. In addition, no appreciable difference in γc is observed in the dense pastes with crystalline and glassy structures which are formed by mono- and bidisperse microgels, respectively. This is in contrast to a finite difference in γc for the crystal and glass formed by the hard sphere reported by Koumakis et al. [Soft Matter, 4, 2008 (2008)]. Furthermore, the highly dense suspensions of NIPA core-NIPMA shell microgels are similar in γc to those of NIPMA microgels. These results indicate that γc for the highly dense suspensions of soft micro-hydrogels depends primarily on the kind of constituent polymer near the particle surface. The yield strain γc is expected to be governed by short-range interactions such as adhesion and friction.
影响因子：
3.9
作者：
Richtering, Walter
通讯作者：
Richtering, Walter