Hofs B, Keizer A de, Stuart M A Cohen
Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands.
J Phys Chem B. 2007 May 24;111(20):5621-7. doi: 10.1021/jp0714318. Epub 2007 May 3.
Using light scattering and cryogenic transmission electron microscopy, we show that highly aggregated polyelectrolyte complexes (HAPECs) composed of poly([4-(2-aminoethylthio)butylene] hydrochloride)49-block-poly(ethylene oxide)212 and poly(acrylic acid) (PAA) of varying lengths (140, 160, and 2000 monomeric units) are metastable or unstable if the method of preparation is direct mixing of two solutions containing the oppositely charged components. The stability of the resulting HAPECs decreases with decreasing neutral-block content and with increasing deviation from 1:1 mixing (expressed in number of chargeable groups) of the oppositely charged polyelectrolytes, most probably for electrostatic reasons. The difference between the metastable and stable states, obtained with pH titrations, increases with increasing PAA length and increasing pH mismatch between the two solutions with the oppositely charged components.
通过光散射和低温透射电子显微镜，我们发现，由聚（[4-（2-氨基乙硫基）丁烯]盐酸盐）49-嵌段-聚（环氧乙烷）212和不同长度（140、160和2000个单体单元）的聚丙烯酸（PAA）组成的高度聚集的聚电解质复合物（HAPECs），如果制备方法是直接混合含有相反电荷组分的两种溶液，则其是亚稳的或不稳定的。所得HAPECs的稳定性随着中性嵌段含量的降低以及相反电荷聚电解质偏离1:1混合（以可充电基团数量表示）程度的增加而降低，这很可能是由于静电原因。通过pH滴定获得的亚稳态和稳态之间的差异，随着PAA长度的增加以及含有相反电荷组分的两种溶液之间pH不匹配程度的增加而增大。
