Conductive Composition Using Non-Conjugated Polymer and Acid Generator
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Solution Overview
Problem
Existing methods for dispersing carbon nanotubes (CNTs) in polymer matrices face challenges such as instability, loss of conductivity, and increased costs due to the use of dopants, which can lead to fragmentation and poor heat resistance, and non-conjugated dispersants often increase contact resistance and reduce transparency.
Innovation Solution
An electrically conductive composition is developed using carbon nanotubes, a non-conjugated polymer dispersant with an aromatic ring, and a neutral acid generator as a dopant precursor that generates cations under external stimuli, allowing for stable dispersion and doping treatment to enhance conductivity without impairing the CNTs' properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive polymer is used as a dispersant, then the conductivity properties of the resulting composition are improved, but this is accompanied by a decrease in transparency due to light absorption by the dispersant
Solution Approach 1:
The invention divides the dispersant system into two separate functional components: a non-conjugated polymer dispersant that maintains transparency and a separate dopant that provides conductivity. This segmentation allows each component to perform its specific function without the trade-off present in conductive polymer dispersants, where the dispersant itself absorbs light. The non-conjugated polymer structure specifically avoids the light absorption issue while the added dopant restores conductivity.
2Illumination intensity
If non-conjugated dispersants are used, then transparency is maintained, but the dispersant increases the contact resistance of the CNTs, preventing the conductive properties from being fully manifested
Solution Approach 1:
The invention introduces a dopant as an intermediary substance that mediates between the non-conjugated polymer dispersant and the CNTs. The dopant acts as a charge transfer agent, facilitating electron transfer to the CNTs and reducing their contact resistance. This intermediary approach allows the system to maintain the transparency benefits of non-conjugated dispersants while overcoming their limitation of increasing contact resistance through the dopant's charge transfer capability.
3Reliability
If dopants are added to a CNT dispersion, then the conductivity of the CNTs is increased, but the dispersed state of the CNTs becomes unstable due to changes in pH or interactions by the dopant
Solution Approach 1:
The invention performs preliminary dispersal of CNTs using a non-conjugated polymer dispersant before adding the dopant. This preliminary action establishes a stable dispersion state that is then maintained during subsequent doping. The non-conjugated polymer provides steric stabilization that prevents aggregation, and because it does not undergo the same pH-sensitive interactions as conductive polymers, the stability is preserved throughout the doping process and in the final composite.
4Stability of the object's composition
If carbon nanotubes are chemically treated to introduce functional groups, then dispersibility is improved, but this leads to fragmentation of the CNTs and a decline in electrical conductivity
Solution Approach 1:
The invention extracts the need for chemical functionalization of CNTs by using a non-conjugated polymer dispersant that achieves dispersibility through physical interactions rather than chemical bonding. This extraction approach avoids the harmful effects of chemical treatment (fragmentation and conductivity loss) while still achieving the desired dispersibility through the polymer's steric stabilization and solubility characteristics.
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
The composition achieves stable dispersion and high electrical conductivity, enabling the use of a variety of base materials and facilitating the formation of thin-films with improved light transmittance and conductivity, suitable for diverse applications.
Implementation Method 1
the dopant precursor is an acid generator which generates cations under the influence of light and/or heat
Data Source
AI summary
A conductive composition containing carbon nanotubes, a carbon nanotube dispersant, and a dopant precursor, wherein the dispersant is a non-conjugated polymer compound having an aromatic ring as the repeating unit, and the dopant precursor is an acid-generating agent which generates cation by being subjected to light and/or heat. The aforementioned conductive composition is capable of stably dispersing carbon nanotubes and of efficiently doping same without damaging the conductive properties of the carbon nanotubes.