Designing multifunctional silica coatings for enhanced broadband antireflection and microfiber contamination sensing

•A facile method for tunable porous and robust multifunctional coatings.•Optimized coatings with excellent broadband AR performance and good durability.•Porous coatings considerably improve the sensitivity of contaminants sensors.•Simple method for manufacturing both broadband AR coatings and contamination sensors.