Polyelectrolytes in alcohol-water mixtures: From counterion solvation to hand sanitisers

醇水混合物中的聚电解质：从抗衡离子溶剂化到洗手液

• 批准号: 466504295
• 负责人: Professor Dr. Walter Richtering
• 金额: --
• 依托单位: Lehrstuhl für Physikalische Chemie II
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/466504295?language=en
• 关键词: Polyelectrolytes; alcohol; water; mixtures; counterion

Hand sanitisers are an important tool to combat the spread of infectious diseases. Unlike hand-washing with soap, they can be readily used without the need of a running water source. Hand sanitisers are typically composed of 80 v/v alcohol and 20 v/v of water at neutral pH. The most common alcohols used are ethanol and isopropanol. Water-alcohol mixtures are low viscosity liquids, a feature that limits their efficacy. To overcome this problem, polymers could be added, however, the high alcohol content of hand sanitisers means that common polymers cannot be used as thickening agents due to their poor solubility in alcohol media. We propose a simple method to improve the solubility of polyelectrolytes in alcohol-water mixtures by using hydrophobic counterions. Polyelectrolytes are already in wide use as gelling agents in pharmaceutical and food products in water-based formulations. Preliminary experiments show that while the sodium salt of carboxymethyl cellulose is insoluble in practically all non-aqueous solvents, its tetrabutyl-ammonium salt readily dissolves in alcohols and alcohol-water mixtures and other organic media. The ion-exchange approach can in principle be used for any ionic (bio-)polymer and has the advantage that it does not require the synthesis of new polymers. Being applicable to a large number of polymers, including some very widely produced biopolymers, the issue of supply in case of a sudden spike in demand can be tackled with the approach proposed. Carboxymethyl cellulose or alginate are already approved by the Federal Drug Agency and European Medicine Agency as are many quaternary ammonium salts. From the fundamental perspective, solutions of polyelectrolytes with hydrophobic ions in alcohols (and other organic media) are interesting because their thermodynamic properties are dictated by energetic counterion-solvent interactions, instead of counterion entropy, as is common for most systems studied thus far. Recent developments in simulation techniques, particularly by Douglas and co-workers, have highlighted the important role of counterion solvation. Counterion solvation has therefore attracted much attention in the last five years and it is thought to be a crucial factor in understanding some of the key conformational, scattering and rheological properties of polyelectrolytes which classical theories are unable to explain.The key challenges are to understand the influence of counterion entropy, counterion solvation, and polymer-solvent interactions on the phase behaviour, structure and rheology of polyelectrolytes in mixed alcohol-water solutions. While the work is motivated by the potential application of polyelectrolytes in hand sanitisers, the knowledge generated in this proposal will lead to a substantial increase in our fundamental understanding of polyelectrolyte thermodynamics.

洗手液是对抗传染病传播的重要工具。与用肥皂洗手不同，它们可以轻松使用，无需自来水源。洗手液通常由 80 v/v 酒精和 20 v/v 中性 pH 值的水组成。 最常用的醇是乙醇和异丙醇。水-酒精混合物是低粘度液体，这一特性限制了其功效。为了克服这个问题，可以添加聚合物，然而，洗手液的高酒精含量意味着普通聚合物由于在酒精介质中的溶解度差而不能用作增稠剂。我们提出了一种简单的方法，通过使用疏水性抗衡离子来提高聚电解质在醇-水混合物中的溶解度。聚电解质已广泛用作水基制剂中的药品和食品中的胶凝剂。初步实验表明，虽然羧甲基纤维素的钠盐几乎不溶于所有非水溶剂，但其四丁基铵盐易​​溶于醇和醇-水混合物以及其他有机介质。 离子交换方法原则上可用于任何离子（生物）聚合物，并且具有不需要合成新聚合物的优点。 该方法适用于大量聚合物，包括一些广泛生产的生物聚合物，因此可以通过所提出的方法解决需求突然激增时的供应问题。羧甲基纤维素或藻酸盐以及许多季铵盐已获得联邦药品管理局和欧洲药品管理局的批准。从基本角度来看，醇（和其他有机介质）中具有疏水性离子的聚电解质溶液很有趣，因为它们的热力学性质是由高能抗衡离子-溶剂相互作用决定的，而不是迄今为止研究的大多数系统常见的抗衡离子熵。模拟技术的最新发展，特别是道格拉斯及其同事的发展，强调了反离子溶剂化的重要作用。因此，反离子溶剂化在过去五年中引起了广泛关注，它被认为是理解聚电解质一些经典理论无法解释的关键构象、散射和流变性质的关键因素。关键挑战是了解反离子熵、反离子溶剂化和聚合物-溶剂相互作用对混合醇-水聚电解质的相行为、结构和流变学的影响 解决方案。虽然这项工作的动机是聚电解质在洗手液中的潜在应用，但该提案中产生的知识将导致我们对聚电解质热力学的基本理解大幅增加。