Graphical Analysis in Gels Morphology I. General Method

Abstract

A new graphical analysis method is proposed for measurement of gels morphology on volume phase transition. Poly(N-isopropylacrylamide) (PNIPA) gels shrink and become white after jumping above the critical temperature. Whitening slowly disappears and the gels become finally transparent. This final stage is regarded as the equilibrium state. The shrinking and whitening of disk-like PNIPA gels have been monitored using a Charge-Coupled Device (CCD) video camera, and both area and whitening of the gels have been evaluated from time-resolved images using a new graphical analysis method. We showed that gels underwent a two-step shrinking in synchronism with the whitening process. To fit the time-dependent shrinking process, the sum of exponential and stretched exponential functions was adequate using the "x 2-map method". The exponent characterizing the stretched exponential was found to be greater than one. The meaning of fitting parameters is determined on the assumption that the skin layer collapses in the second shrinkage.

Analytical Description of Degradation-Relaxation Transformations in Nanoinhomogeneous Spinel Ceramics

“…4, this process can be conditionally reflected as an obvious decreasing tendency between two groups of basins (A and B metabasins). The similar processes are proper to protein chains affected by folding [10–14] or temperature-induced volume phase transitions in poly( N -isopropylacrylamide) [32]. As a result, the overall kinetics of thermally induced degradation-relaxation transformations tends towards CER behavior with over-unity compressibility index β as it is well illustrated in Fig.…”

Assessment of the trackability, flexibility, and conformability of coronary stents: A comparative analysis

“…However, it is noteworthy that a sign of squeezed exponential kinetics can be found in the folding experiment of peptostreptococcal protein L at the condition where the native state stability is significantly enhanced (and hence nonglassy downhill landscape is highly developed) 41. In addition, the squeezed exponential kinetics has also been found experimentally in such phenomena as amyloid formation of β‐lactoglobulin44 and volume relaxation of polymer gels 45. The squeezed exponential kinetics can be used as a convenient indicator of a nonglassy downhill folding process (or a sequential folding process as discussed in the previous work18) and is expected to promote our understanding of the protein‐folding mechanisms in cooperation with further experimental support for the squeezed exponential folding kinetics.…”

Analytical Description of Degradation-Relaxation Transformations in Nanoinhomogeneous Spinel Ceramics

“…4, this process can be conditionally reflected as an obvious decreasing tendency between two groups of basins (A and B metabasins). The similar processes are proper to protein chains affected by folding [10][11][12][13][14] or temperatureinduced volume phase transitions in poly(N-isopropylacrylamide) [32]. As a result, the overall kinetics of thermally induced degradation-relaxation transformations tends towards CER behavior with over-unity compressibility index β as it is well illustrated in Fig.…”