CIQUP, IMS (Institute for Molecular Sciences), Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
CeNTI-Centre for Nanotechnology and Smart Materials, Rua Fernando Mesquita, 4760-034 Vila Nova de Famalicão, Portugal.
Molecules. 2023 Apr 13;28(8):3454. doi: 10.3390/molecules28083454.
Interactions between polymers (P) and surfactants (S) in aqueous solution lead to interfacial and aggregation phenomena that are not only of great interest in physical chemistry but also important for many industrial applications, such as the development of detergents and fabric softeners. Here, we synthesized two ionic derivatives-sodium carboxymethylcellulose (NaCMC) and quaternized cellulose (QC)-from cellulose recycled from textile wastes and then explored the interactions of these polymers with assorted surfactants-cationic (CTAB, gemini), anionic (SDS, SDBS) and nonionic (TX-100)-commonly used in the textile industry. We obtained surface tension curves of the P/S mixtures by fixing the polymer concentration and then increasing the surfactant concentration. In mixtures where polymer and surfactant are oppositely charged (P/S and P/S), a strong association is observed, and from the surface tension curves, we determined the critical aggregation concentration () and critical micelle concentration in the presence of polymer (). For mixtures of similar charge (P/S and P/S), virtually no interactions are observed, with the notable exception of the QC/CTAB system, which is much more surface active than the neat CTAB. We further investigated the effect of oppositely charged P/S mixtures on hydrophilicity by measuring the contact angles of aqueous droplets on a hydrophobic textile substrate. Significantly, both P/S and P/S systems greatly enhance the hydrophilicity of the substrate at much lower surfactant concentrations than the surfactant alone (in particular in the QC/SDBS and QC/SDS systems).
聚合物（P）和表面活性剂（S）在水溶液中的相互作用导致界面和聚集现象，这些现象不仅在物理化学中具有重要意义，而且对许多工业应用也很重要，例如洗涤剂和织物柔软剂的开发。在这里，我们从纺织废料中回收纤维素，合成了两种离子衍生物——羧甲基纤维素钠（NaCMC）和季铵化纤维素（QC），然后研究了这些聚合物与各种表面活性剂（阳离子型（CTAB、双子）、阴离子型（SDS、SDBS）和非离子型（TX-100））的相互作用，这些表面活性剂在纺织工业中广泛使用。我们通过固定聚合物浓度，然后增加表面活性剂浓度，获得了 P/S 混合物的表面张力曲线。在聚合物和表面活性剂带相反电荷的混合物中（P/S 和 P/S），观察到强烈的缔合，并且从表面张力曲线中，我们确定了存在聚合物时的临界聚集浓度（）和临界胶束浓度（）。对于带相似电荷的混合物（P/S 和 P/S），几乎观察不到相互作用，除了 QC/CTAB 系统，它比纯 CTAB 具有更高的表面活性。我们进一步通过测量疏水纺织基底上的水滴滴的接触角，研究了带相反电荷的 P/S 混合物对亲水性的影响。显著的是，与单独的表面活性剂相比，P/S 和 P/S 系统在低得多的表面活性剂浓度下大大提高了基底的亲水性（特别是在 QC/SDBS 和 QC/SDS 系统中）。
