The ion-specific effect on the solubility of macromolecules in water, rationalized through the Hofmeister series, can be used as an effective method to obtain polymer particles with desired microstructural properties thanks to the so-called salting out effect. By choosing the proper salt and optimizing the polymer and the salt concentration, it is possible to tailor the particle structural features like the radius and the degree of compactness and to speed up the aggregation process until complete conversion from free chains to aggregates. Here we rationalize the segregation of poly-ethylene-vinyl alcohol (EVOH) chains in the presence of sodium chloride (NaCl). The effect of polymer and salt concentrations on the kinetics and the thermodynamics of the aggregation process is considered. In particular, we show how such parameters influence the microstructural properties of the particles through a combination of light and neutron scattering techniques as well as microscopy. We found that by increasing sodium chloride concentration it is possible to speed up the aggregation process, obtaining a complete conversion from free chains to aggregates at shorter times, whereas increasing poly-ethylene-vinyl alcohol concentration from 0.70% w/w to 1.30% w/w determines an increase of the microgel size of a two-times factor. Moreover, NaCl concentration directly affects both the packing degree of the polymer chains within the aggregate and the morphology of the polymer particle, leading to a more compact structure at higher NaCl concentrations. Understanding how it is possible to tune both aggregation kinetics and EVOH particle microstructure is fundamental in order to give a general picture which could be broadened to the class of vinyl alcohol-based polymers.

通过所谓的盐析效应，通过Hofmeister系列合理化的对大分子在水中溶解度的离子特异性效应可以用作获得具有所需微结构性质的聚合物颗粒的有效方法。通过选择合适的盐并优化聚合物和盐的浓度，可以调整颗粒的结构特征，例如半径和紧密度，并加快聚集过程，直到从自由链完全转化为聚集体为止。在这里，我们在存在氯化钠（NaCl）的情况下合理化了聚乙烯乙烯醇（EVOH）链的分离。考虑了聚合物和盐浓度对聚集过程的动力学和热力学的影响。尤其是，我们通过光和中子散射技术以及显微镜的结合展示了这些参数如何影响颗粒的微观结构特性。我们发现，通过增加氯化钠的浓度，可以加快聚集过程，在较短的时间内从自由链完全转化为聚集体，而将聚乙烯-乙烯醇的浓度从0.70％w / w增加到1.30％w / w确定两倍的微凝胶尺寸增加。此外，NaCl的浓度直接影响聚集体中聚合物链的堆积程度和聚合物颗粒的形态，从而导致在较高的NaCl浓度下结构更加紧凑。