Aggregates of chemically conjugated microgels regarded as a model of gels

✍ Scribed by Yoshitaka Koshiro; Nobuhiro Morone; Takashi Fukutomi

• Book ID: 103985269
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 755 KB
• Volume: 3
• Category: Article
• ISSN: 0966-7822
• DOI: 10.1016/0966-7822(94)00022-y

✦ Synopsis

In the crosslinking reaction of primary polymers, the rate constant R(i, j) can be described by R(i, j) = i"ja (a 11). Zf a -l/2 or l/2 <a s 1, products are microgels or macrogels, respectively. Clusters of urn-order sizes were prepared by the crosslinking of St(styrene)-HEMA (hydroxyethylmethacrylate) microgels (d = 260 nm) with glutaraldehyde (crosslinking agent) and HCl (catalyst), as a model of gels. These clusters were observed under the microscope. The microscopic negatives of the clusters were illuminated with light and the fractal dimension D of the clusters was determined by the transmittance of the light. The cluster size (O-9/3.0 urn) did not affect the value of D (2.65-2.82). The concentration (0.4-2.0 wt%) of HCl also did not affect D of the clusters. When the microgels were crosslinked in the medium containing NaCl (2 wt%), D decreased (2.11-267).

The 'rapid aggregation' of the gels occurred because of large ionic strength.