Silver Nanowire Polyol Synthesis via Redox Feedback Control
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Solution Overview
Problem
Existing methods for producing silver nanowires face challenges with low yield and high silver concentration, requiring large reactors and significant amounts of solvent, which are economically inefficient and complex.
Innovation Solution
A method involving a reaction mixture with a polyol, an organic chemical that adsorbs on the silver surface, a halide or pseudohalide, and a redox couple, where the silver salt is added at a high temperature to achieve a high yield of silver nanowires with a concentration of at least 0.5% by weight, using bromine, iodine, or vanadium as redox couples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing polyol process methods are used to produce silver nanowires, then the production can be carried out with available chemicals and procedures, but the yield is limited to a maximum of 65% and large reactors with large amounts of solvent are required
Solution Approach 1:
The patent changes the chemical parameters of the reaction system by introducing a specific redox couple (Fe²⁺/Fe³⁺) and controlling the oxidation state of iron during the polyol process. This parameter change enables higher silver concentration (at least 0.5% by weight) and improved yield (at least 80%) without requiring proportionally larger reactor volumes, thus resolving the contradiction between productivity and quantity of substance required.
2Quantity of substance
If high silver concentration is used to improve economic efficiency, then the production cost decreases, but the existing processes cannot achieve both high concentration and high yield simultaneously
Solution Approach 1:
The patent implements feedback control through the iron redox couple system. The Fe²⁺/Fe³⁺ couple monitors and regulates the reduction process of silver ions, ensuring that high silver concentrations (at least 0.5% by weight) are converted efficiently into nanowires with high yield (at least 80%). The redox feedback mechanism maintains optimal reaction conditions throughout the process, enabling simultaneous achievement of high concentration and high productivity.
3Productivity
If large reactors with large amounts of solvent are used to produce economically relevant amounts of silver nanowires, then the total production volume increases, but the process complexity and economic efficiency deteriorate
Solution Approach 1:
The patent changes the chemical parameters by introducing the iron redox couple and optimizing the polyol composition, which enables high silver concentration (at least 0.5% by weight) and high yield (at least 80%). This parameter change allows achieving economically relevant production volumes without proportionally increasing reactor size or process complexity, as the improved efficiency compensates for the reduced solvent-to-product ratio.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the production of silver nanowires with a yield of 80% or more at high silver concentrations, simplifying the process and reducing the need for large reactors and solvents, while maintaining high reaction efficiency.
Implementation Method 1
the silver salt is reduced to metallic silver in the form of nanowires
Implementation Method 2
an organic chemical that adsorbs on the silver surface
Implementation Method 3
a redox couple, where the silver salt is added at a high temperature to achieve a high yield of silver nanowires with a concentration of at least 0.5% by weight, using bromine, iodine, or vanadium as redox couples
Data Source
AI summary
The present invention provides a process for producing silver nanowires. The process comprises the steps of: a) providing a reaction mixture comprising a polyol, an organic chemical which is adsorbed on a silver surface, a chemical which forms a halide and/or one which forms a pseudohalide, the halide-forming chemical being a salt of one of the halides Cl-, Br- and/or I-, and the pseudohalide-forming chemical being a salt of one of the pseudohalides SCN-, CN-, OCN- and/or CNO-, a chemical which forms a redox pair and is selected from the group consisting of bromine, iodine, vanadium and mixtures thereof, b) adding a silver salt in an amount such that the concentration of silver in the reaction mixture is at least 0.5% by weight, based on the total weight of the reaction mixture, the silver salt being added at a temperature of the reaction mixture of at least 100°C, c) maintaining the temperature of the reaction mixture of 100°C for the duration of the reaction.