## 1 Introduction  
Multifunctional transparent coatings are closely related to our lives and are categorized as one of the hot topics of many researchers [1; 2]. While maintaining transparency, the coating is also endowed with multiple properties, such as self-cleaning [3; 4], anti-fogging [5; 6], oil-water separation [7], anti-corrosion [8; 9; 10], anti-reflection [11; 12] and self-healing [13; 14; 15]. There are usually two ways to achieve self-cleaning, the super-hydrophilic surface and the super-hydrophobic surface. When water droplets come into contact with the coating, they will immediately be spread over the entire surface to form a continuous water film, thereby taking away the dirt on the surface [16]. The smooth surface that reduces the scattering of light makes the coating transparent and anti-fogging [5]. On the other hand, when the water droplets come into contact with the coating with low surface tension, the water droplets will keep their spherical shape and roll off quickly from the surface [17]. The preparation of superhydrophobic surfaces often relies on two factors, micro or nano-scaled hierarchical structures [18] and low surface energy materials [19]. In addition, a transparent coating is often used as a protective coating to protect metallic substrates from corrosion, because the dense and inert coating separates the metal from the environment [20]. Furthermore, anti-reflective coatings are often used in solar cells [12]. The refractive index of the antireflective coatings is lower than that of the substrate. Through the interference of light, it effectively reduces the reflection loss of incident light and improves the efficiency of solar cells [21]. What is more, the damaged structure can be recovered spontaneously by self-healing materials with external stimuli [15]. Self-healing coatings repair damage in two ways, inherent reversible noncovalent interactions [22; 23; 24; 25; 26; 27] and dynamic covalent bonds [28; 29; 30; 31; 32]. However, these coatings are often soft and susceptible to scratches and abrasion. Scratches may make the surface rough, which will greatly cause the scattering of light, thereby reducing the transparency of the coating [33]. In addition, self-cleaning, anti-corrosion and other functions may also be affected, which severely restricts its application in daily life. Although the self-healing coating can relieve the effects of scratches to a certain extent, it cannot totally eliminate the damage of scratches [15]. Therefore, scratch resistance is also an important point for transparent coatings. [PERSON] et al. prepared a bilayer antireflective coating with the top layer of ultra-low refractive index from fully dispersing nano-silica particles by mixing HMDS and achieved an average transmittance of 99.90% in the visible region [34]. However, the coating with an ultra-low refractive index was usually rather soft, easily scratched. [PERSON] et al. fabricated a transparent scratch-resistant coating through the direct oxidation of Al-coated glass [35]. After annealing at 600 \({}^{\circ}\)C, the pencil hardness of the coating increased to 9H due to the hard Al\({}_{2}\)O\({}_{3}\) particles. However, the transmittance of the coating declined from 90% to 75%. [PERSON] et al. prepared durable and superhydrophobic fabric coatings through simple mixtures of fluorinated silica nanoparticles and polydimethylsiloxane (PDMS) and showed that the water contact angle only decreased from 170\({}^{\circ}\) to 150\({}^{\circ}\) after 28,000 cycles of abrasion under 12 kPa [36]. However, the transparency of the coating was not mentioned. In general, the epoxy resin needs to be solidified to increase its hardness [37; 38; 39] through a ring-opening reaction to form an organic network. (3-Glycidyloxypropyl) Trimethoxysilane (GLYMO) and (3-Glycidoxypropyl) Triethoxysilane (GPTES) contain epoxy groups, as silane coupling agents, often used as surface hardening agents [37]. [PERSON] et al.