In this paper the effect of two synthetic, pH-responsive co-polymers, U-PVPyPEGMA-H and Q-PVPyPEGMA-H, with pyridine and polyethylene glycol grafts, on silicic acid polymerization is presented. The scope of this work was to evaluate the impact of several experimental parameters, such as working pH, polymer MW, polymer concentration, state of the pyridine ring (non-protonated, protonated, quaternized) on the anticipated inhibitory and/or enhancement activity with regards to silicic acid autocondensation to produce amorphous silica. It was found that pH substantially influences the silicification reaction, either in the absence or presence of the polymers. pH also affects the protonation state of the pyridine N atom. For example, pH switching from 5.0 to 7.0 transforms U-PVPyPEGMA-H from a silica formation catalyst (pH = 5.0) to a silicic acid stabilizer (pH = 7.0). Concentration enhances the role of the polymers, either as silicic acid stabilizers or catalysts. Polymer MW appears to have no effect on their activity either as stabilizers or catalysts. Polymer entrapment in the precipitated amorphous silica matrix occurs under these experimental conditions, affecting particle size, morphology and tendency for aggregation. The state of the N atom on the pyridine ring (non-protonated, protonated, quaternized) exhibits a profound effect on silicic acid autocondensation to produce amorphous silica. Based on our results, a “free” (non-protonated) pyridine ring induces silica inhibition, whereas protonation or quaternization enhances silica formation.

在本文中两个合成，pH响应性的效果共聚物，U形PVPyPEGMA-H和Q-PVPyPEGMA-H，与吡啶和聚乙二醇接枝，提出了硅酸聚合。这项工作的范围是评估几个实验参数的影响，例如工作pH，聚合物分子量，聚合物浓度，吡啶环的状态（非质子化，质子化，季铵化）对预期的抑制和/或增强活性的影响。关于硅酸的自动缩合以生产无定形二氧化硅。发现在不存在或存在聚合物的情况下，pH均显着影响硅化反应。pH还影响吡啶N原子的质子化状态。例如，pH从5.0切换到7.0会转化U-PVPyPEGMA-H从二氧化硅形成催化剂（pH = 5.0）到硅酸稳定剂（pH = 7.0）。浓度增强了聚合物作为硅酸稳定剂或催化剂的作用。聚合物MW作为稳定剂或催化剂似乎对其活性没有影响。在这些实验条件下，聚合物会截留在沉淀的无定形二氧化硅基质中，从而影响粒径，形态和聚集趋势。吡啶环上的N原子状态（未质子化，质子化，季铵化）对硅酸自动缩合产生无定形二氧化硅具有深远的影响。根据我们的结果，一个“自由的”（非质子化的）吡啶环会引起二氧化硅的抑制，而质子化或季铵化则会促进二氧化硅的形成。