Connectivity dependence of gelation and elasticity in AB-type polymerization: an experimental comparison of the dynamic process and stoichiometrically imbalanced mixing

Abstract

Comparison of two methodologies tuning the connectivity of AB-type polymerization shows the applicability of mean-field approximation.

Temperature Dependence of Polymer Network Diffusion

“…[22]). Equation (6) indicates that D is a linear function of G with increasing p, which is consistent with Fig. 2(a).…”

“…Because gelation (i.e., the process of connecting networks) is a dynamic process, it is typically impossible to precisely measure the physical properties at a certain point during gelation using p as a control parameter. To statically replicate the gelation process at any point, we developed a methodology that enables measurements using p as a control parameter [6,7].…”

“…The polymer concentrations (c) were 30, 60, 90, 120 g/L. We mixed the precursor solutions in different proportions of s = 0.35, 0.40, 0.45, 0.50, where s = [tetra-PEG-SH]/([tetra-PEG-MA] + [tetra-PEG-SH]), to obtain gel samples with tuned p after the completion of the reaction as p 2s [6]. All gel samples were used in the as-prepared state.…”

“…5), which is formally identical to Eq. ( 1) for G (meaning "negative energy elasticity" [6]). We note that the actual value of D may not follow the extrapolation lines at low T away from the measured T because coexisting solvent (water) freezes at T 273 K.…”

On-demand retrieval of cells three-dimensionally seeded in injectable thioester-based hydrogels

“…The longer degradation time (t deg ) with higher PEG concentrations can be attributed to the fact that, in the current system, the increase in PEG concentration decreases the critical cross-link density to maintain the gel state, resulting in broadening of the gel region in the sol-gel phase diagram. 30,31 Similar experiments were performed by xing the PEG concentration at 100 g L À1 while varying the concentration of L-cys. The t deg decreased with increasing L-cys content (Fig.…”