###### Abstract  
Outdoor bronze states are constantly exposed to weather conditions and reactive compounds in the atmosphere that can interact with their surfaces. To avoid these interactions, a commonly used method is the application of coatings with corrosion inhibitors. However, a significant limitation of these inhibitors is their gradual loss over time. In this study, we aimed to improve the durability of 5-ethyl-1,3_A_-thiadiazol-2-amine (AEDTA), the inhibitor chosen to formulate new acrylic coatings for outdoor bronzes. Methyl-\(\beta\)-cyclodextrinatrin (Me-\(\beta\)-CD) was selected to host the inhibitor due to the capability of cyclodext to form complexes incorporating small organic molecules. The complexes of Me-\(\beta\)-CD and AEDTA were prepared and the inclusion of AEDTA was proved by Fourier-transform infrared spectroscopy, X-ray diffraction and nuclear magnetic resonance spectroscopy. Then, acrylic coatings were prepared at different concentrations of the Me-\(\beta\)-CD/ AEDTA system. They were thermally aged and monitored every 24 h. To evaluate the volatilization of the corrosion inhibitor, solid phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS) and thermal desorption-GC/MS (TD-GC/MS) analyses were performed during the first 72 h. The results were compared to those of pure AEDTA films and Inclac(r). The outcomes showed that Me-\(\beta\)-CD/ AEDTA complexes are promising candidates for developing coatings with improved stability and longer retention of AEDTA. cyclodext; corrosion inhibitors; bronze status; inclusion complexes; protective coatings +
Footnote †: journal: _molecules_  
0000-0001-9993-3000-00001-9993-3000-0001-9 coating over time [5]. In this study, we propose to improve the permanence of AEDTA in acrylic coatings using methyl-\(\beta\)-cyclodextrintrin (Me-\(\beta\)-CD) as a green nanocontainer for the corrosion inhibitor. Cyclodexttrins (CDs) have gathered significant attention across various scientific disciplines due to their versatility. These water-soluble, macrocyclic oligosaccharides are composed of at least six \(\alpha\)-D-glucopyranoside units linked via \(\alpha\)-(1\(\rightarrow\)4)-glycosidic bonds and are produced through the enzymatic degradation of starch by cyclodextrin glucon-transferase (CGTase) [6]. The outer surface of the molecule is hydrophilic, rendering it water-soluble, while the inner cavity is less hydrophilic, creating a favourable environment for non-polar compounds. Various CD derivatives, such as hydroxypropyl-\(\beta\)-CD and methyl-\(\beta\)-CD, have been developed to improve their performance, including enhanced complexation efficiency and controlled release properties [7]. CDs are extensively used in the pharmaceutical, biomedical, and food industries, and their unique ability to form inclusion complexes with guest molecules has expanded their applications by improving the solubility, stability, and bioavailability of these molecules [8]. Several studies have demonstrated the potential of CDs to host corrosion inhibitors, which are typically small organic molecules [9]. The use of CDs as complexing agents aims to increase the retention of corrosion inhibitors within protective coatings, as these inhibitors often separate and leach out of the film, losing their effectiveness [10]. By incorporating corrosion inhibitors into carriers, such issues can be mitigated [11]. Research has shown that CDs are reliable carriers for this purpose: \(\beta\)-CD has successfully encapsulated 5-mercapto-1-phenyl-tetrazole to improve bronze corrosion resistance [12]; \(\alpha\)- and \(\beta\)-CD complexes with dibenzylthiourea (DBT) enhanced carbon steel corrosion protection by improving DBT's solubility [13]; and \(\beta\)- and \(\gamma\)-CDs complexes with various organic inhibitors have demonstrated improved corrosion resistance for aluminium alloys and zinc [14; 15; 16; 17].