Porous polymer coatings are useful for a broad range of applications including textiles, membranes, and implants. For practical applications, it is critical to have good adhesion between the substrate and the porous polymer coating. We report a solvent-free fabrication technique to create porous polymer coatings with excellent adhesion to a wide range of substrates including rigid, flexible, planar, and curved surfaces. These robust porous coatings can withstand tape tests and scratch tests. The porous coatings are fabricated by polymerization of three monomers: methacrylic acid (MAA) serves as the template for polymerization, glycidyl methacrylate (GMA) promotes adhesion via epoxide functional groups, and ethylene glycol diacrylate (EGDA) improves mechanical strength through cross-linking. An additional dense base layer of poly­(glycidyl methacrylate) (PGMA) serves to anchor the porous coating to the substrate to further improve adhesion. The porous structure of the coating and the adhesion to the substrate were retained after soaking in isopropyl alcohol, methanol, and acetone. The coatings were applied to silicon, polynorbornene rubber, and stainless-steel to demonstrate the versatility of the process. Our solventless fabrication process is versatile and scalable and therefore provides an environmentally friendly alternative to liquid-phase fabrication methods.