Preparation Of Photothermal Conversion Coatings And Lonogels With Healability

Over the past decades,a variety of self-healing materials have been developed to promote the service life and reliability of materials.Self-healing materials can be designed and prepared by encapsulating healing agents or incorporating dynamic chemical bonds including reversible covalent bonds and supramolecular force into materials.As the foundation of modern science such as energy,communications and electronics,functional materials have been widely developed for the practical use in recent years.It provides a reliable guarantee for the development of highly durable and sustainable functional materials by integrating healability into functional materials Among functional materials,photothermal conversion materials and ionogels have attracted a great deal of research interest due to the efficient utilization of solar energy of photothermal conversion materials and the great potential of ionogels in a wide range of applications such as lithium-ion batteries,supercapacitors,and strain sensors.However,the research on the preparation of self-healing photothermal conversion materials and self-healing ionogels is in its infancy.In chapter 1,the classification of self-healing materials and the application of photothermal conversion materials and ionogels were briefly investigated.The research progress on photothermal conversion materials and ionogels with healability was reviewed and discussed.Finally,the existing problems in these researches were summed up and the research purposes of our thesis were identified.In chapter 2,photothermal conversion coatings with self-healing superhydrophobicity were fabricated by spraying a mixture of beeswax,multiwalled carbon nanotubes(MCNTs)and polydimethylsiloxane(PDMS).The resulting photothermal conversion coatings exhibited broadband light absorption ability and can thus efficiently generate steam under sunlight irradiation.Furthermore,the photothermal conversion coatings possess an electric steam generation ability,which allows the coatings to continuously generate steam when sunlight is not available.The integration of superhydrophobicity provides the photothermal conversion coatings with a self-cleaning ability that can prevent the reduction of steam generation efficiency induced by microorganisms and mud in the water.The photothermal conversion coatings are capable of healing damage to their superhydrophobicity through the migration of hydrophobic compounds in beeswax,providing long-lasting protection.Moreover,because the mobility of the hydrophobic compounds in beeswax increases with a temperature rising,the healing ability of the resulting photothermal conversion coatings can be greatly improved by heating at an elevated temperature.The resulting photothermal conversion coatings are capable of rapidly healing damage to their superhydrophobicity in their working environment due to the photothermal and electrothermal abilities of the coatings.Considering their simple preparation process and high cost effectiveness,photothermal conversion coatings with self-healing superhydrophobicity show great application prospects to provide fresh water.In chapter 3,self-healing ionogels with good mechanical properties and excellent ionic conductivity were fabricated for the application as strain sensors by complexing polyvinyl alcohol(PVA)with polyvinylpyrrolidone(PVP)and loading of 1-ethyl-3-methylimidazolium dicyanamide([EMIm][DCA])).PVA can provide good mechanical properties for ionogels and PVP can enhance the compatibility between[EMIm][DCA]and the polymer complex.Such a design endows the resulting ionogels with a high average transmittance of 85%in the visible light region,fracture stress of 3.27 MPa,fracture strain of 803%and room temperature ionic conductivity of 11.3 mS cm-1.The excellent resilience and fatigue resistance of ionogels provide durability for the application as strain sensors.More importantly,the ionogels can restore its structural integrity and pristine mechanical properties after undergoing greater deformation or mechanical damage,leading to the long-term application as strain sensors.