Multiscale Ordering in Hybrid Materials During Reaction-Induced Phase Transitions

Controlling nanoparticle and polymer organization at multiple length scales in hybrid materials has yet to be fully realized. Simply mixing nanoparticles and polymers typically leads to macroscale aggregation. To circumvent the mixing barrier associated with blending nanoparticles and polymers, and to control organization over multiple length scales, a new method, reaction-induced phase transitions (RIPT), is proposed in which monomer is polymerized in the presence of nanoparticles. Here, the presentation will describe how a mixture of oleylamine-functionalized gold nanoparticles (AuNP) dispersed and methyl methacrylate (MMA) that are polymerized lead to hybrid AuNP/poly(methyl methacrylate) (PMMA) materials with multiscale ordering. During the polymerization of MMA in the initially homogeneous AuNP/MMA mixture, the sample undergoes macrophase separation during the reaction. Although the macrophase separation occurs, AuNPs still appear well-dispersed. We find that nanoparticles aggregate when the samples are processed into films due to the removal of unreacted monomer and thermal treatment. The reported results highlight how RIPT is a new method to control the ordering of nanoparticles and polymers at both the nano and macroscales during monomer polymerization.