Ethoquad 18/25 As an Alternate Surfactant for Gold Nanorod Growth
Primary Faculty Mentor’s Name
Dr. John Stone
Proposal Track
Student
Session Format
Poster
Abstract
In the last decade gold nanoparticles’ use as targeting, imaging, and therapeutic agents has increased significantly. Gold’s properties on the nanoscale are attractive owing to their interesting optical properties, non-cytotoxicity, and long-term stability. Gold nanorods are often prepared following a seed-mediated approach whereby gold salts are catalyzed by the addition of small gold spheres (seeds) in the presence of a weak reducing agent and the growth directing surfactant cetyltrimethylammonium bromide (CTAB). CTAB is an alkylammonium salt with a positively charged head group. This surfactant has been shown to be critical for rod growth as it forms a preferential, interdigitated, micellular bilayer on the side faces of the gold during growth promoting a rod-like geometry. While effective, CTAB is environmentally toxic and thus there is a need to explore alternate surfactants for gold nanorod growth that are more environmentally friendly. In the current study, we are growing rods in the much less toxic alkylammonium salt Ethoquad 18/25. Ethoquad 18/25 will form micellular bilayers at appropriate surfactant concentrations and is expected to display preferential binding to the side faces of the gold promoting rod-like growth. Ethoquad 18/25 is used in industry and can be found in many shampoo conditioners. While we have been able to generate rods with this surfactant, the monodispersity is lower as compared to CTAB. Currently, we are varying all reactant concentrations and conditions in an effort to find the ideal growth conditions for rod formation. While synthesizing rods is our ultimate goal, we have been able to reproducibly prepare spheres coated with Ethoquad 18/25 which, to the best of our knowledge, has not yet been reported in the literature. We are also currently investigating the potential to utilize other environmentally friendly surfactants such as sodium dodecyl sulfate (SDS) for gold nanorod growth.
Keywords
Nano, Chemistry, Gold, Nanorod, Surfactant, Green chemistry
Location
Concourse/Atrium
Presentation Year
2014
Start Date
11-15-2014 2:55 PM
End Date
11-15-2014 4:10 PM
Publication Type and Release Option
Presentation (Open Access)
Recommended Citation
Melvin, Michael, "Ethoquad 18/25 As an Alternate Surfactant for Gold Nanorod Growth" (2014). Georgia Undergraduate Research Conference (2014-2015). 121.
https://digitalcommons.georgiasouthern.edu/gurc/2014/2014/121
Ethoquad 18/25 As an Alternate Surfactant for Gold Nanorod Growth
Concourse/Atrium
In the last decade gold nanoparticles’ use as targeting, imaging, and therapeutic agents has increased significantly. Gold’s properties on the nanoscale are attractive owing to their interesting optical properties, non-cytotoxicity, and long-term stability. Gold nanorods are often prepared following a seed-mediated approach whereby gold salts are catalyzed by the addition of small gold spheres (seeds) in the presence of a weak reducing agent and the growth directing surfactant cetyltrimethylammonium bromide (CTAB). CTAB is an alkylammonium salt with a positively charged head group. This surfactant has been shown to be critical for rod growth as it forms a preferential, interdigitated, micellular bilayer on the side faces of the gold during growth promoting a rod-like geometry. While effective, CTAB is environmentally toxic and thus there is a need to explore alternate surfactants for gold nanorod growth that are more environmentally friendly. In the current study, we are growing rods in the much less toxic alkylammonium salt Ethoquad 18/25. Ethoquad 18/25 will form micellular bilayers at appropriate surfactant concentrations and is expected to display preferential binding to the side faces of the gold promoting rod-like growth. Ethoquad 18/25 is used in industry and can be found in many shampoo conditioners. While we have been able to generate rods with this surfactant, the monodispersity is lower as compared to CTAB. Currently, we are varying all reactant concentrations and conditions in an effort to find the ideal growth conditions for rod formation. While synthesizing rods is our ultimate goal, we have been able to reproducibly prepare spheres coated with Ethoquad 18/25 which, to the best of our knowledge, has not yet been reported in the literature. We are also currently investigating the potential to utilize other environmentally friendly surfactants such as sodium dodecyl sulfate (SDS) for gold nanorod growth.