Date of Award
2023
Document Type
Open Access Dissertation
Department
Chemistry and Biochemistry
First Advisor
Brian Benicewicz
Abstract
This dissertation focuses on the design, synthesis, and characterization of well controlled interfaces on nanoparticle surfaces. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize block copolymers and polymer grafted silica nanoparticles (PGNs) with precise control over molecular weight, graft density, and architectures.
In the first chapter, polymer molecular weights were determined through diffusion ordered spectroscopy NMR (DOSY NMR) as an alternative to size exclusion chromatography (SEC). Polymer standards of known molecular weight were analyzed through DOSY to obtain their respective diffusion coefficients. A calibration curve was generated correlating diffusion coefficients with polymer molecular weights. The reliability of the calibration curve was tested by comparing the molecular weights from DOSY to SEC from synthesized polymers. The accuracy of DOSY to determine polymer molecular weights was suitable for polymers of narrow dispersity below 1.3. Furthermore, incorporation of solvent viscosity in the calibration curve led to a near “universal” calibration curve for various solvents.
In the following chapter, we investigated the synthesis and application of polyoligoaniline grafted nanoparticles to mimic the gas separation properties of polyaniline and enhance permeability. The polyoligoaniline, poly(dianiline) (PDA), exhibited a high glass transition temperature and resulted as a powder. To promote film formation, poly(methyl acrylate) (PMA) was incorporated onto the nanoparticle surface to form a PDA/PMA bimodal grafted nanoparticle. The mechanical properties and gas separation of these materials was investigated and discussed in detail.
An extension of this work saw the development of an alternative mode to synthesize viable films containing grafted polyoligoaniline for gas separation. Keeping with the film formation properties of PMA, grafted block copolymers of polyoligoanilines and PMA were synthesized. RAFT polymerization was utilized for the selective placement of oligoanilines in the grafted chains. The gas separation performance varied considerably depending on the location of the oligoaniline in the grafted block copolymer. Furthermore, redox properties were investigated between the oligoaniline Dianiline and Trianiline and their polymeric counterparts. The properties are discussed further in the chapter.
Departure from oligoanilines leads to the synthesis and challenges of developing cyclic polymer grafted nanoparticles which is discussed in detail. Specialized RAFT agents designated to graft to silica oxide nanoparticles were developed to promote controlled cyclic polymers from the nanoparticle surface. The challenges and outcomes are discussed in detail.
Finally, some conclusions about what was learned as well as some suggestions about how this work might proceed are offered in light of the work presented herein.
Rights
© 2023, Eric Gerald Ruzicka
Recommended Citation
Ruzicka, E. G.(2023). Synthesis and Characterization of Polymer Grafted Nanoparticles. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/7884