Ghosh Richa, Bentil Sarah A, Juárez Jaime J
Department of Mechanical Engineering, Iowa State University, Ames, IA 50011, USA.
Center for Multiphase Flow Research and Education, Iowa State University, Ames, IA 50011, USA.
Polymers (Basel). 2024 Oct 11;16(20):2875. doi: 10.3390/polym16202875.
In this investigation, we explored the microrheological characteristics of dilute hydrogels composed exclusively of Poly(vinyl) alcohol (PVA), Phytagel (PHY), and a blend of the two in varying concentrations. Each of these polymers has established applications in the biomedical field, such as drug delivery and lens drops. This study involved varying the sample concentrations from 0.15% to 0.3% (/) to assess how the concentration influenced the observed rheological response. Two probe sizes were employed to examine the impact of the size and verify the continuity hypothesis. The use of two polymer blends revealed their immiscibility and tendency to undergo phase separation, as supported by the existing literature. Exploring the microrheological structure is essential for a comprehensive understanding of the molecular scale. Dynamic light scattering (DLS) was chosen due to its wide frequency range and widespread availability. The selected dilute concentration range was hypothesized to fall within the transition from an ergodic to a non-ergodic medium. Properly identifying the sample's nature during an analysis-whether it is ergodic or not-is critical, as highlighted in the literature. The obtained results clearly demonstrate an overlap in the results for the storage (G') and loss moduli (G″) for the different probe particle sizes, confirming the fulfillment of the continuum hypothesis.
在本研究中，我们探究了仅由聚乙烯醇（PVA）、植物胶（PHY）以及二者不同浓度混合物组成的稀水凝胶的微观流变学特性。这些聚合物中的每一种在生物医学领域都有既定的应用，如药物递送和眼药水。本研究涉及将样品浓度从0.15%变化到0.3%（/），以评估浓度如何影响观察到的流变学响应。采用了两种探针尺寸来研究尺寸的影响并验证连续性假设。正如现有文献所支持的，两种聚合物混合物的使用揭示了它们的不混溶性和发生相分离的倾向。探索微观流变学结构对于全面理解分子尺度至关重要。选择动态光散射（DLS）是因为其频率范围广且应用广泛。所选的稀浓度范围被假设处于从遍历介质到非遍历介质的转变范围内。正如文献中所强调的，在分析过程中正确识别样品的性质（无论其是否遍历）至关重要。所得结果清楚地表明，不同探针颗粒尺寸的储能模量（G'）和损耗模量（G''）结果存在重叠，证实了连续性假设的成立。
