Hexagonal Boron Nitride Nanoparticle Stabilization
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Solution Overview
Problem
The poor stability of dispersed hexagonal boron nitride nanoparticles in heat transfer fluids limits their application, as they are not suitable for high-temperature conditions encountered in many heat transfer applications.
Innovation Solution
Incorporating a triblock copolymer with a central hydrophobic block of polypropylene glycol surrounded by hydrophilic blocks of polyethylene glycol into a continuous phase containing hexagonal boron nitride nanoparticles, which stabilizes the dispersion at both room temperature and elevated temperatures, enhancing the thermal conductivity and stability of the nanofluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hexagonal boron nitride nanoparticles are dispersed in heat transfer fluids to improve thermal conductivity, then thermal conductivity is improved, but stability deteriorates
Solution Approach 1:
A triblock copolymer with a central hydrophobic polypropylene glycol block and hydrophilic polyethylene glycol blocks is introduced as an intermediary substance. The hydrophobic block adsorbs onto the nanoparticle surface while the hydrophilic blocks extend into the aqueous phase, creating steric stabilization that prevents aggregation and maintains dispersion stability at elevated temperatures
Solution Approach 2:
The patent creates a composite system combining hexagonal boron nitride nanoparticles with a triblock copolymer surfactant in an aqueous base fluid. This composite approach integrates the high thermal conductivity of the nanoparticles with the stabilizing properties of the copolymer, achieving both improved thermal performance and long-term stability
2Productivity
If nanoparticles are used to enhance heat transfer capability, then heat transfer performance is improved, but reliability deteriorates due to poor stability at high temperatures
Solution Approach 1:
The patent modifies the chemical composition parameters by selecting specific block lengths in the triblock copolymer (where n and y are integers between 50-200), optimizing the hydrophobic-hydrophilic balance to maintain nanoparticle dispersion stability at elevated temperatures up to 85°C and beyond
Data Source
AI summary
A composition includes a continuous phase of water, alcohol, or a mixture of water and alcohol; hexagonal boron nitride nanoparticles dispersed in the continuous phase; and a compound having a formula (I)or a salt thereof, wherein n is an integer between 50 and 200 and y is an integer between 20 and 200.