Carboxylic multi-walled carbon nanotubes are widely used in various fields due to their unique properties. In the field of electronics, they are utilized to enhance the conductivity and mechanical strength of composite materials, making them ideal for use in flexible electronics and sensors. Their high surface area and functional groups make them excellent candidates for use in energy storage devices, such as supercapacitors and batteries, where they improve charge storage and transfer efficiency.

In the biomedical sector, these nanotubes are employed in drug delivery systems due to their ability to carry and release therapeutic agents in a controlled manner. They are also used in tissue engineering to create scaffolds that promote cell growth and regeneration. Additionally, their ability to bind with various biomolecules makes them useful in biosensors for detecting diseases and monitoring biological processes.

In environmental applications, carboxylic multi-walled carbon nanotubes are used in water purification systems to remove contaminants and heavy metals through adsorption. They are also incorporated into filtration membranes to enhance their efficiency and durability. Overall, their versatility and functional properties make them valuable in advancing technology and improving various industrial and scientific applications.