Molecular dynamics study of polymeric chemical gels: Effect of persistence length and crosslinker density

PEREYRA, RODOLFO G.; CARIGNANO, MARCELO A.

JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS

JOHN WILEY & SONS INC

Año: 2019 vol. 57 p. 1343 - 1350

0887-6266

Using molecular dynamics, we study the formationof chemical gels from an initial solution of reactive polymersthat undergo a crosslinking reaction. We study the effect of thepolymer persistence length and different densities of cros-slinkers along the chains. As the reaction progresses, differentstructural features are identified in the system leading to thedevelopment of a percolated cluster. These features are(a) single strands, (b) double strands, and (c) bridges. We foundthat the total numbers of these three kinds of features areroughly independent of the persistence length; however, theaverage lengths of single and double strands grow with this var-iable. The average length of double strands strongly increaseswith increasing crosslinker density and the amount of single strands sharply falls as crosslinker density grows. We alsofound that general structural features of polymer networks arehighly dependent on chain persistence length and crosslinkerdensity. Fully flexible chains with high density of crosslinkersresult in inhomogeneous network structures with large voids. Incontrast, precursor chains with high rigidity and scarce numberof crosslinkers result in homogeneous networks having smallcavities.