04022ntm a2200301 i 4500003000800000005001700008006001900025007000300044008004100047020003300088040002700121100003700148245015500185264003600340264001200376300005800388336002100446337002500467338002300492347002400515500005900539502009000598504003800688520284900726610007403575650004503649650002603694MY-KuUP20260525113618.0t||||fr|||| 000 0 ta260525t20262026my a|||fr|||| 000 0 eng d  aTHE0010524 (Local)qHardback  aUMPSAbengcUMPSAerda1 aYasin M. Y. Albarqouni,eauthor.10aElucidating the protective mechanism of self-healing pd-z@msn coating on microbial influenced corrosion of aluminium surface /cYasin M. Y. Albarqouni 1aKuantan, Pahang :bUMPSA,c2026 4c© 2026  axviii, 167 pages :billustration ;c30 cm.+e1 CD-ROM  2rdacontentatext  2rdamediaaunmediated  2rdacarrieravolume  2rdaatext filebPDF  aFaculty of Chemical and Process Engineering Technology  aThesis (Doctor of Philosophy) -- Universiti Malaysia Pahang Al Sultan Abdullah - 2026  aInclude bibliographical reference3 aMicrobial-influenced corrosion (MIC) remains a critical challenge in marine and industrial applications, where traditional protective coatings lack the dual functionality needed to simultaneously inhibit corrosion and bacterial proliferation. Existing solutions often fail to provide controlled, stimuli-responsive release of inhibitors, leading to inefficient protection and premature coating failure. This research bridges that gap by developing an innovative, pH and temperature-responsive nanocomposite (PD-Z@MSN) for use in a smart epoxy coating. The study involved the synthesis of zinc oxide (ZnO) nanoparticles via Sol-gel, their encapsulation within mesoporous silica nanoparticles (MSN) synthesized by a modified Stöber method, and subsequent functionalization with polydopamine (PDA) to form the final PD-Z@MSN composite. Comprehensive characterization using FT-IR, XRD, XPS, FESEM, and Hr-TEM confirmed the composite’s spherical morphology (43–120 nm), high crystallinity, and successful integration of components, with PDA acting as a stimuli-responsive gatekeeper. Antibacterial testing against Escherichia coli and Bacillus cereus demonstrated strong efficacy, with inhibition zones of 11.80 mm and 11.56 mm, respectively, even at low concentrations. Density functional theory (DFT) analysis provided a molecular-level explanation, revealing the high electrophilicity and strong binding affinity of the composite, which facilitates interactions with bacterial cells and enhances reactive oxygen species (ROS) generation, leading to oxidative stress and apoptosis. Electrochemical corrosion evaluations revealed outstanding performance, with the optimized PD-Z@MSN/epoxy coating achieving a corrosion rate of only 0.0002 mm·y⁻¹ and a polarization resistance of 1.18 × 105 Ω·cm2 after 120 hours in 3.5% NaCl, corresponding to 98.7% inhibition efficiency, performance that meets and exceeds relevant ASTM standards for protective coatings. These results are directly linked to the composite’s proposed dual-action mechanism. For corrosion, the PDA shell responds to environmental stimuli, releasing Zn2+ ions that react with chlorides and hydroxides to form a protective layer of Zn(OH)2 on the aluminum substrate, effectively blocking anodic and cathodic sites. For antibacterial action, the same controlled release delivers ZnO, which generates bactericidal ROS, while PDA itself disrupts bacterial membranes and proteins. In conclusion, this research successfully designed and validated a dual-functional PD-Z@MSN/epoxy coating. Its intelligent, controlled-release mechanism provides a synergistic defense, combining potent, DFT-supported antibacterial action with superior, electrochemically-verified corrosion resistance. This offers a promising and advanced solution for combating MIC in demanding environments.20aFaculty of Chemical and Process Engineering TechnologyxDissertations 0aUniversities and collegesxDissertations 0aThesesxDissertations