A study of stress development in aqueous gelatin coatings

Abstract

A cantilever deflection technique was used to monitor stress during the drying of aqueous gelatin coatings. Photographic-grade gelatin was dissolved in deionized water and coated, chilled, and dried. The final average in-plane tensile stress ranged from 0 to 50 MPa. Measured stresses were independent of the coating thickness and initial solution concentration. At low relative humidity (0%) and low drying temperature (ϳ 20°C), the stress grew with time, reaching a constant average magnitude of 46 MPa. Raising the relative humidity above 0% or raising the temperature above 50°C changed the manner in which stress evolved. Stress rose to a peak value and then relaxed to a lower final value. Humidity affected stress evolution more than did temperature, within the limits of this work.

The Origin of Surface Stress Induced by Adsorption of Iodine on Gold

“…Cantilever beams are employed widely for the measurement of surface stress, both in macroscopic systems [1][2][3][4] and in microscopic systems. [5][6][7][8] In sensor technologies, surface stress can be used to follow the adsorption of molecules, 5,6,8,[9][10][11] temperature changes, 12,13 and changes in surface charge.…”

Freezing/thawing effects on the exfoliation of montmorillonite in gelatin‐based bionanocomposite

“…The amide I band is originated from C¼ ¼O stretching vibrations coupled to NAH bending vibration. 33,34 Hence, the higher crystallinity of FG0 gives higher TS. 38 Figure 6(A) shows that the positions of B, I, and II amide bands in G-1MMT and G-10MMT are nearly unchanged while the amide A shifts to low-frequency shoulder in comparison with G0.…”

“…Initial grip separation and mechanical crosshead speed were set at 25 and 100 mm/min, respectively. 33,34 In the present work, G-MMT bionanocomposites were obtained by conditioning the gelatin-MMT mixture at 25 C for 48 h. During this period, low degree of renaturation is attained. Figure 1 shows the XRD patterns of G-MMT and FG-MMT bionanocomposites with various MMT contents.…”

“…Below 35 C, gelatin macromolecules partially renature into their original collagenlike helical structure. 33,34 In the present work, G-MMT bionanocomposites were obtained by conditioning the gelatin-MMT mixture at 25 C for 48 h. During this period, low degree of renaturation is attained.…”

“…It has been reported that the gelatin with high crystallinity (triple-helix content) was stronger. 33,34 Hence, the higher crystallinity of FG0 gives higher TS. Furthermore, Table II shows that the TS of FG-MMT bionanocomposites is both higher than that of G-MMT bionanocomposites with the same MMT content.…”