Chitosan Microspheres as Carriers for pH‐Indicating Species in Corrosion Sensing. Issue 2 (26th December 2019)

• Record Type: Journal Article
• Authors: Sousa, Isabel; Quevedo, Marcela C.; Sushkova, Alesia; Ferreira, Mário G. S.; Tedim, João
• Is Part Of: Macromolecular materials and engineering. Volume 305:Issue 2(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-12-26
• Subjects: chitosan microspheres -- controlled release studies -- corrosion studies -- pH‐sensing species; Plastics -- Periodicals; Polymers -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1002/mame.201900662
• Languages: English
• ISSNs: 1438-7492

Abstract

Abstract: Chitosan microspheres containing bromocresol green, cresol red, and phenolphthalein for corrosion detection, through pH change, are synthesized in order to be used in protective coatings for aluminium alloys. Microspheres containing corrosion detection species are characterized morphologically (SEM) and physico‐chemically (FTIR, TGA). Release studies (UV–vis) are performed in corrosion‐promoting conditions (pH, NaCl), and detection studies by immersion in media associated with corrosion activity while microspheres' sensing activity is evaluated visually. Electrochemical characterization of AA2024 substrates in the presence of chitosan spheres is performed to understand material performance, and a color change is observed as a result of local pH increase in cathodic areas when corrosion takes place. These findings can be correlated with the results from release studies and seem a promising approach for corrosion sensing purposes, not only because pH increase is possible to detect due to corrosion, but also because chitosan is considered an environmentally friendly material. Abstract : This work describes the successful synthesis of microspheres containing pH‐indicating species for corrosion detection. The obtained materials are able to change color, associated with pH indicator pKa and assigned to changes in the alkaline direction as a result of cathodic activity. These findings open prospects for the use of the prepared materials in functional coatings for corrosion sensing.