An electrochemical, cationic, surfactant-selective sensor based on multiwalled carbon nanotubes (MWCNT) functionalized with a sulfate group and the cetylpyridinium ion (MWCNT–OSO₃⁻CP⁺) as a sensing material was used for optimization of the formulation of a fabric softener. Potentiometric titrations were performed and response measurements were obtained using four cationic surfactants (CS) of technical grade and four CS of analytical grade. The slope closest to Nernstian was obtained for di-(tallow carboxyethyl) hydroxyethyl methylammonium methosulfate (MAS) (59.5 ± 1.1 mV/decade of activity in water and 57.5 ± 1.3 mV/decade of activity in CaCl₂). When using CS as analytes in potentiometric titrations, the best accuracy (99.8%) was obtained when using MAS; therefore, it was chosen as the CS for the fabric softener formulation. Due to the better properties of fabric softeners with silicone in their formulations, four silicones at several concentration levels were used as potential additives. Based on the stability and viscosity of the system, the diquaternary polydimethylsiloxane (DPS) (w = 0.19%) was chosen for the fabric softener formulation. The pH did not significantly influence the potential when in the range of 3–8 or the recovery of potentiometric titrations when in the range of 3–7. The application profile of the CS was assessed through streaming potential measurements of reference fabrics in an electrokinetic analyzer. The obtained electrokinetic parameters indicated on lag in adsorption of model fabric softener (MFS) based on MAS (w = 9%), with the addition of silicone DPS (MFS 3), on cotton and polyester fabrics, but advantage in stability when compared with other MFS investigated.

中文翻译：

---

使用电化学传感器和流动电位测量优化织物柔软剂配方

一种基于多壁碳纳米管 (MWCNT) 的电化学、阳离子、表面活性剂选择性传感器，用硫酸根和十六烷基吡啶鎓离子 (MWCNT–OSO ₃ ⁻ CP ⁺ ) 作为传感材料，用于优化织物柔软剂的配方. 使用四种工业级阳离子表面活性剂 (CS) 和四种分析级 CS 进行电位滴定并获得响应测量值。最接近 Nernstian 的斜率是针对二（牛油羧乙基）羟乙基甲基硫酸铵 (MAS) 获得的（水中活性为 59.5 ± 1.1 mV/十年，CaCl _{2 中}的活性为 57.5 ± 1.3 mV/十年）。在电位滴定中使用 CS 作为分析物时，使用 MAS 获得最佳准确度 (99.8%)；因此，它被选为织物柔软剂配方的 CS。由于配方中含有有机硅的织物柔软剂具有更好的特性，因此使用了不同浓度水平的四种有机硅作为潜在添加剂。基于体系的稳定性和粘度，双季聚二甲基硅氧烷 (DPS) ( w = 0.19%) 被选为织物柔软剂配方。pH 在 3-8 范围内时不会显着影响电位或在 3-7 范围内时电位滴定的恢复。CS 的应用概况是通过电动分析仪中参考织物的流电势测量来评估的。获得的电动参数表明基于 MAS 的模型织物柔软剂 (MFS) 的吸附滞后 ( w  = 9%)，添加有机硅 DPS (MFS 3)，在棉和涤纶织物上，但在稳定性方面具有优势其他 MFS 调查。