Smart Polymer-Grafted Silica: Synthesis and Characterization

Abstract

Colloidal particles have properties based on size and have the potential to better explain molecular systems. Smart polymers are chains of repeating subunits that have the unique ability to change properties based on an external stimulus such as temperature of pH. Our goal is to synthesize and characterize smart polymer-grafted colloidal silica particles in order to observe a combination of properties from both systems. Silica particles were synthesized using the Stober growth process, which allowed for controlled particle growth around a fluorescent dye. Atom transfer radical polymerization (ATRP) was used to graft the smart polymer, poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA), from functionalized silica particles. PDMAEMA is a known smart polymer that changes its polarity based on temperature, pH, and molecular weight. To confirm polymer synthesis, infrared spectroscopy and gel permeation chromatography were completed. The use of confocal laser scanning microscopy allowed imaging for the polymer-grafted particles through both time-scans and z-scans. These scans enabled observation of particle movement in 3D as the temperature and pH were changed. Observations concerning the synthesis and behavior of smart polymer-grafted silica can be used for applications ranging from 3D printing to enhance oil recovery.