Continuous Millifluidic Surface Modification of Synthesized Silver Nanowires

Summary

Destinee Williams, a PhD student in Chemical Engineering at Oklahoma State University, presents her research on the continuous millifluidic surface modification of silver nanowires. The study explores innovative methods to synthesize and stabilize silver nanowires for transparent conductive films. By using a polyol process and surface modification with palladium, the research aims to overcome silver's instability and oxidation. Key findings show that millifluidic synthesis yields more consistent nanowires compared to batch processes. The future direction includes a green synthesis approach using brown sugar and integrating the process with 3D printing technology to create advanced conductive materials.

Takeaways

• 😀 The research focuses on synthesizing and modifying the surface of silver nanowires for use in transparent conductive films (TCFs).
• 😀 Silver is chosen for its excellent electrical conductivity, thermal properties, transparency, and mechanical flexibility.
• 😀 The polyol process is used for synthesizing silver nanowires, with ethylene glycol as the reducing agent and solvent, and silver nitrate as the metal precursor.
• 😀 A key challenge with silver is its susceptibility to oxidation, which can increase sheet resistance in transparent conductive films.
• 😀 The surface modification process involves the deposition of palladium on the silver nanowires via a galvanic reaction, which helps stabilize the nanowires.
• 😀 Millifluidic synthesis was preferred over batch synthesis as it provides better control over the reaction and favors nanowire morphology over nanoparticles.
• 😀 The continuous surface modification process aims to integrate both the synthesis of silver nanowires and surface modification into one continuous workflow.
• 😀 Batch synthesis leads to a mixture of nanoparticles and nanowires, while millifluidic synthesis produces more consistent nanowires.
• 😀 Palladium deposition on the surface of silver nanowires was successfully achieved using both batch and semi-continuous methods, with sodium hydroxide enhancing resistance to oxidation.
• 😀 Future experiments will explore a green process by replacing ascorbic acid with brown sugar as a reducing agent, and the integration of 3D printing for TCF production is also in development.

Q & A

What is the main goal of Destinee Williams' research on silver nanowires?

The main goal of the research is to synthesize and modify silver nanowires for use in transparent conductive films, while stabilizing them to prevent oxidation and maintain their performance in applications like electronics and photovoltaics.

Why was silver chosen for the nanowires in this research?

Silver was chosen for its excellent thermal and electrical conductivity, mechanical flexibility, high transparency, and relatively easy and economical synthesis process.

What is the polyol process, and why was it used for synthesizing silver nanowires?

The polyol process involves using ethylene glycol as a solvent and reducing agent to convert silver nitrate into silver nanowires. It was used because it is a relatively simple, cost-effective method that can produce high-quality nanowires with good control over their size and morphology.

What challenges does silver face when used in nanowire applications, and how are these challenges addressed?

Silver is prone to oxidation, which can compromise its electrical conductivity. The surface modification process, particularly using palladium (Pd), helps stabilize the silver nanowires by preventing oxidation and improving their performance in transparent conductive films.

What is the advantage of using a millifluidic reactor for nanowire synthesis over a traditional batch process?

The millifluidic reactor offers better control over reagent addition, a closed reaction environment, and the ability to consistently produce nanowire morphology, unlike batch processes that result in a mixture of nanoparticles and nanowires, affecting reproducibility.

How does palladium contribute to the surface modification of silver nanowires?

Palladium undergoes a galvanic reaction with silver, where it replaces silver on the surface of the nanowires. This deposition improves the nanowires' stability, especially against oxidation, making them more suitable for long-term use in electronic applications.

What did the semi-continuous surface modification process reveal about the feasibility of continuous surface modification?

The semi-continuous process showed that palladium could still be successfully deposited on the surface of silver nanowires even when the nanowires were suspended in ethylene glycol, proving that the surface modification could work under more continuous conditions.

What are the expected benefits of switching from ascorbic acid to brown sugar as the reducing agent?

Switching to brown sugar would make the reduction process more environmentally friendly by using a more sustainable and natural reducing agent, contributing to a greener, more eco-friendly process.

What role does the 3D printer play in this research?

The 3D printer is used to fabricate transparent conductive films by printing silver nanowires onto various substrates, allowing for the creation of flexible and transparent electronics. It is part of the long-term goal to integrate nanowire synthesis, surface modification, and printing into a continuous process.

How does the integration of the millifluidic reactor, surface modification, and 3D printing contribute to the research objectives?

Integrating the millifluidic reactor for continuous nanowire synthesis, the surface modification process, and the 3D printing of conductive films helps streamline the production process, making it scalable, efficient, and suitable for real-world applications like flexible electronics.