In the field of polymer materials, coatings and adhesives are often confused due to their similar appearance—both are liquid or semi-solid, form polymer films after being applied to substrates, and exhibit "stickiness". However, industry experts point out that the fundamental difference between the two lies in their core design objectives, focusing on "surface issues" and "structural issues" respectively, which determines their application logic and technical paths. The core mission of coatings is to address surface functional needs. By forming a continuous and stable functional film on the substrate surface, they achieve protection, decoration, or isolation. Engineers are most concerned about whether the film maintains coverage integrity; failure forms such as craters, chalking, and aging essentially result from the loss of surface functions. Coatings do not need to be part of the structure—even if they are thin, brittle, and unable to bear loads, they are generally considered acceptable as long as surface functions are not extensively lost. Adhesives, on the other hand, focus on ensuring structural integrity. They need to connect multiple components into a reliably load-bearing whole. The key lies in establishing a stable force transmission path to ensure effective force transfer between components under conditions such as vibration and high temperatures. Technical focus is centered on mechanical properties such as shear strength, creep resistance, and fatigue resistance. Molecular design pursues high molecular weight, strong chain entanglement, and energy dissipation capabilities. Insiders indicate that the key to distinguishing the two is not "whether they are sticky" but their design intentions. This cognitive difference also influences practitioners' technical choices—for example, the application scenario of acrylic resin depends on whether it is used to achieve surface functions or structural connections. Currently, relevant technical exchange communities are continuously expanding, providing accurate communication platforms for practitioners and promoting technological innovation and application upgrading in these two sub-fields. For more information, you can click: https://www.tiktok.com/@mia_iot