Hydrophobically associating water-soluble polymers (HAWSPs), which possess surfactant and polymer properties, are extensively studied. This research work presents a novel HAWSP, poly(acrylic acid-alkyl polyoxyethylene acrylate) (P(AA-AAEO_n)), synthesized by aqueous polymerization of acrylic acid and alkyl polyoxyethylene acrylate (AAEO_n) with various ethoxy groups. The structure of P(AA-AAEOn) was characterized using Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies. The association behavior in the solution was also evaluated through surface tension, dynamic light scattering, and rheology measurements. The findings exhibited that P(AA-AAEO_n) demonstrated noteworthy surface activity, which was amplified as the proportion of the hydrophobic group increased and could effectively reduce the water surface tension. When the concentration reached 0.01%, P(AA-AAEOn) in the solution changed from intramolecular association to intermolecular association. Additionally, P(AA-AAEO_n) manifested notable shear resistance, shear recovery, and viscoelasticity, transitioned from energy elasticity to entropy elasticity in P(AA-AAEO_n) molecules between 25 and 35 ℃. The experimental phenomena and mechanisms resulting from the association behavior of polymer molecules have undergone careful analysis. The elastic conversion of polymer molecules at varying temperatures is a noteworthy finding, which has not been extensively documented in earlier research works. A detailed analysis of this phenomenon has been conducted. However, further research is crucial to establish the prevalence of this phenomenon in HAWSPs.

Graphical abstract

中文翻译：

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聚丙烯酸-聚氧乙烯丙烯酸烷基酯两亲共聚物的缔合行为及溶液性质研究

疏水缔合水溶性聚合物（HAWSP）具有表面活性剂和聚合物特性，受到广泛研究。这项研究工作提出了一种新型HAWSP，聚（丙烯酸-烷基聚氧乙烯丙烯酸酯）（P（AA-AAEO _n）），是通过丙烯酸和具有各种乙氧基的烷基聚氧乙烯丙烯酸酯（AAEO _n）的水聚合合成的。使用傅里叶变换红外 (FTIR) 和核磁共振 (NMR) 光谱对 P(AA-AAEOn) 的结构进行了表征。还通过表面张力、动态光散射和流变学测量来评估溶液中的缔合行为。研究结果表明，P(AA-AAEO _n )表现出显着的表面活性，并且随着疏水基团比例的增加而增强，可以有效降低水的表面张力。当浓度达到0.01%时，溶液中的P(AA-AAEOn)由分子内缔合转变为分子间缔合。此外，P(AA-AAEO _n )表现出显着的剪切阻力、剪切恢复和粘弹性，在25~35 ℃之间P(AA-AAEO _n )分子从能量弹性转变为熵弹性。聚合物分子缔合行为产生的实验现象和机制经过了仔细的分析。聚合物分子在不同温度下的弹性转化是一个值得注意的发现，但在早期的研究工作中尚未广泛记录。对此现象进行了详细分析。然而，进一步的研究对于确定 HAWSP 中这种现象的普遍性至关重要。

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