The gelation process has been explained in the framework of percolation models. Although the percolation models accurately predict the gelation behaviors above the overlap concentration of prepolymers (c*0), they do not predict the gelation behaviors below c*0. We measured the osmotic pressure during the gelation of a series of model polymer gels, namely, tetra-polyethylene glycol (PEG) gels. The osmotic pressure decreased during the gelation reaction and was constant after the sol–gel transition. These results suggest that the clusters grow and fill the system at the sol–gel transition point. As a result, the gels behaved as semidilute systems regardless of the initial polymer concentration. This representation of the sol–gel transition at the overlap condition of the critical clusters corresponds well to the aggregation process predictrion. These results will help better understanding of general percolation problems in the dilute regime. The osmotic pressure during the gelation process below the overlapping concentration of prepolymers was investigated using a series of model polymer gels, namely, tetra-polyethylene glycol gels. The osmotic pressure decreased during the gelation reaction and was constant after the sol–gel transition, suggesting that the clusters grow and fill the system, at the sol–gel transition point. This representation of the sol–gel transition at the overlapping condition of the critical clusters corresponds well to the aggregation process prediction.

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渗透过程中稀释系统的簇生长

凝胶化过程已经在渗透模型的框架中进行了解释。尽管渗流模型准确地预测了高于预聚物重叠浓度 (c*0) 的凝胶行为，但它们无法预测低于 c*0 的凝胶行为。我们测量了一系列模型聚合物凝胶（即四聚乙二醇 (PEG) 凝胶）凝胶化过程中的渗透压。渗透压在凝胶反应过程中降低，在溶胶-凝胶转变后保持不变。这些结果表明簇在溶胶-凝胶转变点生长并填充系统。结果，无论初始聚合物浓度如何，凝胶都表现为半稀释系统。这种在临界簇重叠条件下溶胶-凝胶转变的表示很好地对应于聚集过程的预测。这些结果将有助于更好地理解稀释方案中的一般渗透问题。使用一系列模型聚合物凝胶，即四聚乙二醇凝胶，研究了低于预聚物重叠浓度的凝胶过程中的渗透压。渗透压在凝胶反应过程中降低，在溶胶-凝胶转变后保持不变，表明在溶胶-凝胶转变点，簇生长并填充系统。这种在临界簇重叠条件下溶胶-凝胶转变的表示与聚集过程预测很好地对应。使用一系列模型聚合物凝胶，即四聚乙二醇凝胶，研究了低于预聚物重叠浓度的凝胶过程中的渗透压。渗透压在凝胶反应过程中降低，在溶胶-凝胶转变后保持不变，表明在溶胶-凝胶转变点，簇生长并填充系统。这种在临界簇重叠条件下溶胶-凝胶转变的表示与聚集过程预测很好地对应。使用一系列模型聚合物凝胶，即四聚乙二醇凝胶，研究了低于预聚物重叠浓度的凝胶过程中的渗透压。渗透压在凝胶反应过程中降低，在溶胶-凝胶转变后保持不变，表明在溶胶-凝胶转变点，簇生长并填充系统。这种在临界簇重叠条件下溶胶-凝胶转变的表示与聚集过程预测很好地对应。