Utilization of SiO2 Nanoparticles in Developing Superhydrophobic Coatings for Road Construction: A Short Review

Abstract

The application of superhydrophobic (SH) coatings in road construction has attracted growing attention due to their potential to improve surface durability, reduce cracking, and enhance skid resistance. Among various materials, SiO₂ nanoparticles have emerged as key components in SH coatings by contributing essential surface roughness and hydrophobicity. This review paper analyzes the role of SiO₂ nanoparticles in enhancing the water-repellent properties of coatings applied to road surfaces, particularly concrete and asphalt. Emphasis is placed on their influence on road longevity, reduced maintenance, and overall performance under adverse weather conditions. Furthermore, this review compares functionalization techniques for SiO₂ using different hydrophobic modifiers, evaluating their efficiency, cost effectiveness, and scalability for large-scale infrastructure. In addition to highlighting recent advancements, this study discusses persistent challenges-including environmental compatibility, mechanical wear, and long-term durability-that must be addressed for practical implementation. By offering a critical assessment of current approaches and future prospects, this short review aims to guide the development of robust, high-performance SH coatings for sustainable road construction.

Keywords: SiO2 nanoparticles; UV resistance; anti-icing properties; asphalt and concrete coatings; mechanical stability of coatings; nano-silica application; pavement durability; road construction; self-cleaning surfaces; superhydrophobic coatings; water-repellent coatings.

Figure 1

Schematic representation of the surface modification of dye-doped silica nanoparticles using a water-in-oil microemulsion. After 24 h of synthesis, the nanoparticles undergo surface modification via co-hydrolysis of tetraethyl orthosilicate (TEOS) and organosilane reagents for an additional 24 h. Final purification is performed through ethanol washing. Redrawn and adapted from Bagwe et al. [82] for clarity.

Figure 2

Comparative flowchart showing the preparation of silica nanoparticles via the sol–gel and vapor deposition methods. The sol–gel method involves hydrolysis and condensation of a precursor solution, while the vapor deposition route proceeds through decomposition and oxidation of a volatile precursor.

Figure 3

(a) Schematic reaction mechanism of hexadecyltrimethoxysilane (HDTMS) hydrolysis and condensation with silica surface –OH groups. (b) Surface modification of nano-SiO₂ with HDTMS resulting in a hydrophobic surface, as indicated by the increase in water contact angle from 25.8° (bare SiO₂) to 170.9° (HDTMS-functionalized SiO₂) [91].

Figure 4

Flow diagram for the synthesis of superhydrophobic emulsion coating material (redrawn based on [78]).

Figure 5

Schematic illustration of micro/nano-structured silica deposition on an RTV surface, inspired by the method described in Peng et al., 2018 (redrawn based on [77]).