Graphene-Polymer Compounding via Electrospray Coating
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Solution Overview
Problem
The challenge lies in achieving effective dispersion and de-agglomeration of graphene nanoflakes in polymer matrices, as they tend to aggregate due to strong van der Waals interactions, limiting the realization of graphene's exceptional properties in composite materials.
Innovation Solution
A method involving electrospray coating techniques is employed to de-agglomerate and exfoliate graphene nanoflakes, utilizing their electrostatically chargeable properties to achieve uniform dispersion on non-conductive polymer hosts, such as particles, pellets, and fibers, preventing restacking and enhancing interface interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graphene nanoflakes are added to polymer matrices, then electrical and thermal conductivity is improved, but graphene tends to aggregate due to strong van der Waals interactions, reducing dispersion quality
Solution Approach 1:
The patent uses an electrospray coating system as an intermediary device that applies electrostatic forces to graphene nanoflakes during the coating process. The electrospray nozzle generates highly charged graphene nanoflakes that are deposited onto polymer substrates, using the electrostatic field as a mediator to overcome van der Waals attraction and prevent aggregation, thereby achieving both good dispersion and conductivity.
Solution Approach 2:
The patent changes the electrical charge parameter of graphene nanoflakes by applying high voltage through the electrospray system. This parameter change from neutral to highly charged state fundamentally alters the interaction between graphene nanoflakes, transforming the dominant force from attractive van der Waals forces to repulsive electrostatic forces, enabling uniform dispersion while maintaining conductivity.
2Ease of manufacture
If conventional mixing methods are used to disperse graphene, then processing is simple, but graphene aggregation occurs, limiting interface interaction with polymer matrices
Solution Approach 1:
The patent replaces conventional mechanical mixing methods with an electrospray coating system that uses electrostatic forces for dispersion. Instead of relying on mechanical shear and impact forces that require high energy input and complex equipment, the electrospray system uses electrical fields to achieve uniform dispersion, maintaining ease of manufacture through a straightforward coating process while dramatically improving dispersion uniformity.
3Reliability
If high graphene loading is used to ensure conductivity, then electrical properties improve, but material cost increases and processing complexity increases
Solution Approach 1:
The patent changes the electrical charge parameter of graphene nanoflakes using electrospray technology, which enables effective dispersion at very low loading levels (0.1-5 wt%). This parameter change allows achieving percolation thresholds and desired conductivity at much lower concentrations than conventional methods, reducing material cost and simplifying processing since less graphene needs to be handled and processed.
Solution Approach 2:
The electrospray coating system acts as an intermediary that enables efficient graphene-polymer interface interaction at low loading levels. The electrostatic field ensures uniform distribution and strong adhesion of graphene nanoflakes to the polymer matrix, achieving effective conductivity with minimal graphene content, thereby reducing both material cost and processing complexity.
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 results in well-dispersed graphene/polymer compounds suitable for large-scale production, improving mechanical, electrical, and thermal properties of the materials, even at low graphene loading levels, and allows for further processing via extrusion or injection molding.
Implementation Method 1
taking advantage of the highly electrostatically chargeable properties of graphene to de-agglomerate and further exfoliate the graphene nanoflakes in-situ
Implementation Method 2
The graphene nanoflakes are transferred to a spray nozzle and the spray nozzle is charged to a high voltage to induce an electrostatic charge in the graphene nanoflakes. The electrostatically charged graphene nanoflakes are transferred from the spray nozzle to the bed
Implementation Method 3
Due to the strong van der Waals interaction between layers of graphene, graphene nanoflakes, particularly those having low-defect basal structures, tend to aggregate to give larger particles
Data Source
AI summary
Embodiments described herein relate generally to the production of graphene/polymer compounds. In some embodiments, a method for producing graphene/polymer compounds includes compounding graphene nanoflakes with non-conductive polymer hosts via electrospray coating techniques, taking advantage of the highly electrostatically chargeable properties of graphene to de-agglomerate and further exfoliate the graphene nanoflakes in-situ, and providing uniform and well-dispersed graphene nanoflake coating on various non-conductive polymer hosts, such as polymer fine particles, pellets, fibers, fabrics, non-woven, film, and formed articles. In some embodiments, the deposition of the graphene nanoflakes onto the hosts may be performed in combination with other components, such as but not limited to metal oxides and polymers. The method can be a batch or a continuous process, and is suitable for large scale production of graphene coated materials such as graphene/polymer compound, which can be further processed by, for example, extrusion, compression molding, or injection molding, to yield formed articles.