Rheological and Tribological Behavior of Gels and Emulsions Containing Polymer and Phospholipid,ACS Applied Polymer Materials

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Rheological and Tribological Behavior of Gels and Emulsions Containing Polymer and Phospholipid
ACS Applied Polymer Materials ( IF 4.4 ) Pub Date : 2020-03-04 , DOI: 10.1021/acsapm.0c00053
Barbara V. Farias ₁ , Lilian C. Hsiao ₁ , Saad A. Khan ₁

Affiliation

Oil-in-water (O/W) emulsions are widely used in food, pharmaceutical, and personal care applications. These types of systems often contain hydrophobically modified polymers and phospholipids, where the polymer acts as a rheology modifier or emulsifier, while the phospholipid acts as a functional performance surfactant. However, the underlying mechanism through which the different components affect rheological and tribological characteristics is not well understood. To this end, we take a hierarchical approach, evaluating first the hydrophobically modified polymer alone, followed by polymer and phospholipid and then an O/W emulsion stabilized with the polymer or the phospholipid and polymer combined. We characterize the tribological behavior using a soft model contact consisting of polydimethylsiloxane (PDMS), which has elastic modulus similar to human skin. Bulk rheology results show that the studied systems are shear thinning and have gel-like behavior with elastic modulus increasing substantially upon phospholipids addition. Friction coefficients increase in the elastohydrodynamic regime with increasing sample viscosity. However, systems containing the hydrophobically modified polymer and phospholipids show a lower friction coefficient at the boundary regime. Adsorption studies with a quartz crystal microbalance with dissipation (QCM-D) measurements show that phospholipids are being adsorbed onto the PDMS surface. Confocal laser scanning microscopy of the PDMS surfaces before and after immersion in a hydrophobically modified polymeric suspension containing rhodamine B shows the presence of the polymer on the PDMS surface even after DI water rinse, indicating polymer adsorption, thus resulting in lower friction coefficients at low speeds.

中文翻译：

含聚合物和磷脂的凝胶和乳液的流变和摩擦学行为

水包油（O / W）乳液广泛用于食品，药品和个人护理应用中。这些类型的系统通常包含疏水改性的聚合物和磷脂，其中聚合物充当流变改性剂或乳化剂，而磷脂充当功能性表面活性剂。但是，人们对不同组分影响流变学和摩擦学特性的潜在机理尚不十分了解。为此，我们采用分级方法，首先评估疏水改性的聚合物，然后评估聚合物和磷脂，然后评估用聚合物或磷脂和聚合物结合稳定的O / W乳液。我们使用由聚二甲基硅氧烷（PDMS）组成的软模型触点来表征摩擦学行为，具有与人体皮肤相似的弹性模量。大量的流变学结果表明，所研究的体系是剪切稀化的并且具有凝胶状行为，并且随着磷脂的添加，弹性模量显着增加。摩擦系数在弹性流体力学中随样品粘度的增加而增加。但是，含有疏水改性聚合物和磷脂的体系在边界处表现出较低的摩擦系数。带有耗散的石英晶体微天平（QCM-D）测量的吸附研究表明，磷脂被吸附到PDMS表面上。在浸入含有若丹明B的疏水改性聚合物悬浮液中之前和之后，PDMS表面的共聚焦激光扫描显微镜观察表明，即使在去离子水冲洗后，PDMS表面仍存在聚合物，

更新日期：2020-04-23

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