Preparation And Properties Of Bionic Antireflective Film Based On Rose Structure

With the rapid development of human society and the liberation of social productivity,people rely more and more on energy.Solar energy is favored by people as a clean and renewable energy source,but optical loss is a major obstacle to solar energy utilization efficiency.Reflection has also become one of the hot spots of scientists' research.At present,the important way to reduce optical loss is to use antireflection coatings and anti-reflection structures.Anti-reflection coatings are one or more thin-film coatings deposited on the surface of the substrate,but their poor mechanical properties,narrow wavelength and incident angle ranges,material selection,film thickness control,and material diffusion have led to the introduction of antireflection structures.The anti-reflection structure is to prepare high and low undulating surface structures on the surface of the material to reduce the reflectivity of the material surface.Although the anti-reflection coating and the anti-reflection structure are based on optical principles,the scale requirements are very strict,so it is difficult to process and prepare.At present,there are many methods for preparing anti-reflection structures,for example,laser lithography,machining,chemical modification,etching and other physical and chemical methods,but for complex three-dimensional micro-nano structures,a single preparation method has certain limitations and is difficult to achieve Precise preparation of anti-reflection structure.Therefore,finding a suitable preparation method to fabricate the three-dimensional micro-nano structure is still a major challenge in the preparation process of the anti-reflection film.In order to survive better,creatures in nature have been constantly mutated,evolved,and optimized so that they have an excellent anti-reflection three-dimensional micro-nano body surface structure.This three-dimensional micro-nano structure can accurately replicate the organism through a certain method.The template can be used to realize the large-area preparation of anti-reflection film;These delicate biological structures also provide references and ideas for the design of high-efficiency anti-reflection structures.We can imitate the high-efficiency bionic anti-reflection structure films prepared by these anti-reflection structures.In this paper,red rose petals are selected as the research object,focusing on the micro-nano structure anti-reflection mechanism of the petals and the bionic design and preparation technology.First,clean and shape the petal surface.Secondly,the structure of the petal surface was observed and characterized using an electron microscope,and it was found that the front surface was formed by densely arranging micro-scale papillae,and the papillary surface was also covered with a double-layer hierarchical structure formed by nanoscale folds,That is,the combination of micro-scale papillae and nanoscale folds.Then,according to the microscopic characterization parameters,the modeling software is used to reconstruct the petal micro-nano structure in a threedimensional visualization model to provide support for the design of the petal-like thin film and the interpretation of the anti-reflection mechanism.Using soft etching method,laser etching technology and material-structure coupling method,with petals as the prototype,by adjusting the process parameters and reaction conditions in the preparation process,it overcomes the difficulty of peeling the petals against the material during the soft etching process.Due to difficulties,a micro-nano structure imitating red rose petals was successfully prepared,and a PDMS-based bionic anti-reflection film was obtained.The study found that the bionic anti-reflection film prepared by the soft etching method "inherited" the characteristic structure of the rose petals to achieve the "like" purpose,but the size of the soft etching template is limited by the size of the petals and cannot be larger.The anti-reflection film is prepared,so the laser etching technology can enlarge the template area,but the film prepared by the laser etching technology only has a single structure of petal micron papillae,and finally the antireflection with micro-nano structure is prepared by the material-structure coupling method For the thin film,the latter two methods make the prepared anti-reflection structure close to the petal micro-nano structure,which provides a good idea for the subsequent large-area film preparation.The reflectance,contact angle,self-cleaning and anti-erosion measurements and tests were carried out on the three bionic antireflection films.The results show that the reflectivity of the three films is relatively low,namely 1.5%,4%,and 1%.The anti-reflection effect is obvious.The film surface also has super-hydrophobic properties,self-cleaning properties and anti-erosion properties.