Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
Shayla Chavis - North Carolina Central University
Co-Author(s): Elvis McFee, North Carolina Central University; Selina Arrington-Boyd, North Carolina Central University, Durham; Mauricio Terrones, Pennsylvania State University
Graphene is commonly known as honeycomb-shaped sheets of carbon and has several favorable properties such as flexibility as well as conductivity. Although graphene has been processed for applications, for example, electronics, research regarding the compound’s solubility has not been conducted. Smart polymer brushes, poly(n-isopropylacrylamide) (polyNIPAAm) and poly(acrylic acid) (polyAAc), grafted from the surface of graphene will enable soluble graphene nanosheets. Stimulating graphene’s solubility will allow the graphene product further significance and application. NIPAAm and AAc were polymerized in order to test the hypothesis that polymer brushes can increase graphene’s solubility. Atom transfer radical polymerization was used to synthesize four polyNIPAAm homopolymers (4.09 – 14.4 kg/mol) using a CuBr catalyst system in conjunction with methyl 2-chloropropionate as the initiator and tris[2-(dimethylamino)ethyl]amine as the ligand. Two poly(tBA) homopolymers (11.2-14.1 kg/mol) were synthesized using a CuBr/N’,N’N”,N”- pentamethyldiethylenetriamine catalyst system in conjunction with an alkyl bromide as the initiator. The polymers were analyzed to determine their glass transition temperature, molecular weight, and phase transition temperature (polyNIPAAm). The phase behavior of the polyNIPAAm samples ranged from 32 – 42°C. The glass transition temperature of polyNIPAAm increased from 133-175°C as the molecular weight of the homopolymers increased from 4.0 -14.4 kg/mol. The glass transition temperature of polytBA homopolymers increased from 174-199°C as the molecular weight of the homopolymers increased from 11.2-14.1 kg/mol. Future work will involve the synthesis of random, alternating, and block copolymers of NIPAAm and tBA. This work will also include grafting the polymer brushes from the surface of graphene oxide to be functionalized with 2-Bromoisobuty bromide. These stimuli responsive homopolymers will modify the surface properties of graphene, thus, expanding the use of graphene for new applications.P-NIPAAM & P-tBA Abstract(1).docx
Funder Acknowledgement(s): This work is supported by the National Science Foundation (DMR1523617).
Faculty Advisor: Darlene Taylor, email@example.com
Role: I have made 3 samples of polyNIPAAm and characterized them for specific molecular weight, phase transition, and confirmed through NMR testing. I have also made 2 samples of polytBA and characterized them for specific molecular weight, phase transition, and confirmed through NMR testing.