João Tedim

• PhD in Physical Chemistry
• Professor (Associate) at CICECO-University of Aveiro

Metal corrosion is a colossal technical, economic, and environmental challenge worldwide. Protective coatings containing corrosion inhibitors (CIs) are commonly used to address this natural process, particularly severe in immersed structures...

This review examines copper corrosion mechanisms and their key influencing factors, including micro-structure effects, surface treatments, manufacturing conditions, temperature, water chemistry parameters, fluid velocity, and microbial effects in water-based systems, with a particular focus on heat exchangers. This addresses a critical gap in the e...

Engineered nanomaterials (ENMs), such as silica mesoporous nanocapsules (SiNC), have emerged as a powerful tool for the controlled delivery and release of active compounds in various fields. However, the environmental impact of SiNC on marine biota, particularly when they enter the marine environment through wastewater effluents or direct release f...

This study reports the development of anticorrosive bilayer coatings consisting of in situ grown layered double hydroxides (LDH) covered with a polyurethane layer on a steel substrate. This design aims at providing corrosion protection via the controlled release of gluconate from LDH near the substrate, while at the same time contributing to the im...

The machine learning framework reported herein can greatly accelerate the development of more effective and sustainable corrosion inhibitors for aluminum alloys, which still rely mostly on the experience of corrosion scientists, and trial and error laboratory testing. It can be used to design inhibitors for specific applications, which can be immob...

Nowadays, drug delivery systems (DDSs) are gaining more and more attention. Conducting polymers (CPs) are efficiently used for DDS construction as such systems can be used in therapy. In this research, a well-known CP, polypyrrole (PPy), was synthesized in the presence of the polysaccharide heparin (HEP) and chlorpromazine (CPZ) using sodium dodecy...

Among the Design of Experiments (DoE) approaches available, the Taguchi method offers a methodical and effective way to optimize designs with fewer experimental trials. The effects of deposition conditions on the final properties of boron-doped diamond (BDD) films for water treatment applications deposited in a Hot Filament Chemical Vapor Depositio...

The present investigation was carried out to develop dense ceramics of silicon nitride-titanium nitride (Si3N4–TiN) with low electrical resistivity and excellent mechanical properties. The objective was to employ these ceramics as substrates of conductive diamond electrodes produced by chemical vapor deposition (CVD) for electrochemical application...

Layered hydroxide salt and layered double hydroxide intercalated respectively with molybdate (LHS-M) and gluconate (LDH-G) were used together for corrosion protection of carbon steel for the first time. Essays revealed that inhibitor release from LHS-M and LDH-G occurred in presence of chloride anions, within different timescales. Electrochemical s...

Mesoporous silica engineered nanomaterials are of interest to the industry due to their drug-carrier ability. Advances in coating technology include using mesoporous silica nanocontainers (SiNC) loaded with organic molecules as additives in protective coatings. The SiNC loaded with the biocide 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT), i.e....

The detection of corrosion at early stages could increase the service life of metal-based infrastructures in a cost-effective manner. Despite the recent progress in “smart” self-reporting corrosion sensing coatings, the development of environmentally friendly systems appropriate for steel substrate used in offshore applications remains a relevant c...

Spirocyclic rhodamine derivatives have great potential to be used as fluorescent sensors. Rhodamine B hydrazide (RBH) and its derivatives have been employed to detect various analytes. The interactions of a sensor with an analyte might result in the protonation or hydrolysis of the sensor. Understanding these processes is useful for developing new...

Layered double hydroxides (LDHs) are stimuli-responsive anionic nanoclays. The vast possibilities of using LDHs can lead to their existence in the ecosystem, raising a question of potential ecological concern. However, little is known about the effect of these nanomaterials on freshwater organisms. The present study aimed to assess the ecotoxicolog...

Boron-doped diamond (BDD) electrodes are eco-friendly and widely used in efficient water remediation through electrochemical advanced oxidation processes (EAOPs). These anodes can completely mineralize a wide range of pollutants, only requiring electrical energy. Over the last two decades, numerous commercially available BDD electrodes have emerged...

Re-evaluation of conventional wastewater treatment processes is of paramount importance to improve the overall quality of our aquatic environment. Electrochemical Advanced Oxidation Processes (EAOPs) are the most promising alternative methods with application in wastewater treatment facilities since in situ electrogenerated oxidant agents degrade a...

Herewith, an overview of the group's collaborative research efforts on the development and deployment of computational approaches to understand materials and tools at different length and time scales is presented. The techniques employed range from quantum mechanical approaches based on the density functional theory to classical atomistic and coars...

This work describes the main advances carried out in the field of corrosion protection using layered double hydroxides (LDH), both as additive/pigment-based systems in organic coatings and as conversion films/pre-treatments. In the context of the research topic “Celebrating 20 years of CICECO”, the main works reported herein are based on SECOP’s gr...

A classical molecular dynamics (MD) model of fully unconstrained layered double hydroxide (LDH) particles in aqueous NaCl solution was developed to explore the initial stages of the anion exchange process, a key feature of LDHs for their application in different fields. In particular, this study focuses on the active corrosion protection mechanism,...

Presented in the section "Selected papers of the Frontiers Special Issue Celebrating 20 years of CICECO"

Over the past years, the use of layered materials such as clay minerals, layered double hydroxides, and layered hydroxide salts, as nanocontainers of corrosion inhibitors has grown, and these materials have proved to be very advantageous to improve the corrosion protection of metallic surfaces. The layered materials are especially advantageous for...

Boron-doped diamond (BDD) thin films hold great promise for the future of water remediation, being able to completely mineralize persistent pollutants into CO2 and water, requiring only electrical energy through electrochemical oxidation. However, the main challenges encountered in applying BDDs on a large scale relate to the substrate material. El...

Layered double hydroxides (LDHs) are regarded as potential adsorbents for water treatment from a wide range of pollutants. However, there are only a few studies concerning application of LDHs for elimination of microorganisms from aquatic systems. In this work, experiments were conducted to investigate the efficiency of commercial synthetic hydrota...

Alginate (ALG) is a natural polymer used in a wide range of applications. Cerium is a sustainable corrosion inhibitor for many metal substrates. In this study, ALG/Ce3+ hydrogel microparticles are presented as an innovative cerium(III) reservoir system for the smart release of cerium ions. The active corrosion inhibition capacity of the ALG/Ce3+ co...

The large amount of corrosion inhibition efficiencies in literature, calls for a more efficient way to organize, access and compare this information. The CORDATA open data management application (https://datacor.shinyapps.io/cordata/) can help select appropriate corrosion inhibitors for application specific challenges.

Sodium carboxymethylcellulose (CMC-Na) microparticles, containing corrosion inhibitor benzotriazole (BTA), were prepared using different spray drying processing parameters, with the purpose of future application in protective coatings for the delivery of corrosion inhibitors. The effects of the processing parameters, such as inlet temperature and s...

Corrosion is an environmental and economic global problem. “Smart” or stimuli-responsive colorimetric nanosensors for maritime coatings have been proposed as an asset to overcome the limitations of the current monitoring techniques by changing color in the presence of triggers associated with the early stages of corrosion. Layered double hydroxides...

Microplastics and nanomaterials are applied in a myriad of commercial and industrial applications. When leaked to natural environments, such small particles might threaten living organisms' health, particularly when considering their potential combination that remains poorly investigated. This study investigated the physiological and biochemical ef...

Gold nanoparticles (AuNPs) have been deposited on titania nanotubular layers (TNT) via photocatalytic deposition, and the activity of the obtained AuNPs-TNT systems toward oxygen electroreduction reaction (ORR) in an alkaline medium has been studied and compared with the activity of AuNPs-TNT composites prepared from Au colloidal solutions. Two pho...

The Oxygen Evolution Reaction (OER), half-reaction of the water-splitting process for hydrogen production, suffers from sluggish kinetics. NiFe materials appeared as interesting catalytic materials for this reaction in alkaline electrolyzers and have been studied, particularly in the form of NiFe Layered Double Hydroxides (LDH). However, the impact...

Biofouling prevention is one of the biggest challenges faced by the maritime industry, but antifouling agents commonly impact marine ecosystems. Advances in antifouling technology include the use of nanomaterials. Herein we test an antifouling nano-additive based on the encapsulation of the biocide 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT)...

MgCa and MgGd series of alloys are often reported as promising candidates for biomedical applications. In the present study, cytotoxicity and corrosion behavior of Mg1Ca and Mg10Gd alloys in different electrolytes (NaCl, PBS, MEM) have been investigated in order to make a direct comparison and understand the mechanisms behind their performance. Pot...

Organic corrosion inhibitors embedded in coatings play a crucial role in substituting for traditional anti-corrosion pigments, which can cause acute toxicity problems to human health and the environment [...]

The MarTERA project "SMARTAQUA" is developing an eco-friendly and low-cost early corrosion detection that can be applied on maritime steel structures. • Hexacyanoferrate ions [Fe(CN) 6 ] 3-, which can react with Fe 2+ ions generated from the corrosion of steel giving a blue colour "signal", were incorporated in layered double hydroxides (Mg-Al LDH)...

Featured Application The black coatings described in this work find application in decorative finishes, optical instruments, and photovoltaic modules. Abstract This work compares different electrodeposition procedures to produce nickel black coatings as greener and less toxic alternatives to Cr(VI)-based coatings used in different applications. Ni...

The in-situ detection of corrosion and failures represents an important stage in the procedures of maintenance of metallic structures. The use of nanotechnology embedded in the protective coatings is a promising way to develop user-friendly and cost-effective corrosion detection systems and has to be explored by the coating industry. Several groups...

Encapsulation of active agents (corrosion inhibitors, pH indicators) has been described as a promising approach to impart controlled release and limit detrimental interactions between the active agents and the coating matrix. Mesoporous silica nanocapsules (SiNC) are engineered materials widely used for encapsulation. One synthesis route reported i...

Among the many potential applications of graphene and graphene-based materials, their use as protective films or as additives in coatings for corrosion protection has seen an increased level of interest in the last decade. Much of this interest is motivated by the need to implement additional functionalities, to enhance anti-corrosion performance a...

In this work the ZnAl-NO2 LDH (layered double hydroxide) is investigated as a possible additive for mitigating the chloride-induced corrosion of steel in reinforced concrete. The investigation focused on the stability and chloride binding capacity of this LDH in the pH range typical of cementitious materials. Until pH = 12.5 the material was stable...

A surface layer separating the metal from the environment is often the simplest method of corrosion control. This chapter presents an overview of the coatings used for protecting metals against corrosion, with emphasis on emergent “smart” and self-healing coatings. This chapter begins with a general view of the metallic corrosion process, mechanism...

Silica mesoporous nanocapsules are a class of “smart” engineered nanomaterials (ENMs) applied in several fields. Recent studies have highlighted that they can exert deleterious effects into marine organisms, attributed to the use of the toxic cationic surfactant N-hexadecyl-N,N,N-trimethylammonium bromide (CTAB) during the synthesis of ENMs. The pr...

The structure and composition of a zinc‑aluminum layered double hydroxide (Zn2Al LDH) with the intercalated 2-mercaptobenzothiazole corrosion inhibitor (a.k.a. benzo[d]thiazole-2-thiol) are interpreted by means of atomistic molecular dynamics (MD) simulations. The results concerning the proportion of intercalated 2-mercaptobenzothiazole and water s...

The search for new alternatives to replace chromate-based coatings is a matter of great importance. Since their official ban due to the raised concerns of hexavalent chromium to the human health and the environment, significant efforts have been devoted to finding a more suitable alternative for the corrosion protection of aluminum alloys. However,...

Results of experimental characterisation and modelling of mechanical behaviour of microcapsules for self-sensing polymer composites are presented. Melamine–formaldehyde microcapsules were selected for this purpose. The average diameter, size distribution, and shell thickness of microcapsules were evaluated from scanning electron microscopy images....

Gordaite (NaZn4(OH)6SO4Cl·6H2O) is a mineral from the layered hydroxide salts (LHS) family that presents both cation- and anion-exchange properties, which is rare in this class of materials, having then called much attention lately due to its interesting potential applications. Sharing similar layered structure and composition, gordaite's non-catio...

This work describes the synthesis and characterization of Zn‐Al and Mg‐Al layered double hydroxides (LDHs) intercalated with hexacyanoferrate. X‐ray diffraction, infrared spectroscopy and scanning electron microscopy indicated a successful intercalation of hexacyanoferrate in the sub‐micrometer sized platelet‐like particles. Release studies of hexa...

This work investigated the use of ZnAl-layered double hydroxide (LDH) intercalated with nitrate or nitrite ions for controlling the corrosion of steel in reinforced concrete. The work started by analyzing the stability of the powder in the 1–14 pH range and the capacity for capturing chloride ions in aqueous solutions of different pH. The effect of...

Organic corrosion inhibitors are playing a crucial role to substitute traditional protective technologies, which have acute toxicity problems associated. However, why some organic compounds inhibit corrosion and others do not, is still not well understood. Therefore, we tested different machine learning (ML) methods to distinguish efficient corrosi...

Cationic surfactants are surface-active compounds that can be found in many products, including household and cleaning agents. As a consequence, they tend to be discarded into water streams, ultimately ending up in the aquatic environment. In spite of this environmental issue, studies describing their effects towards marine species are lacking. The...

Biopolymeric microspheres containing corrosion inhibitor benzotriazole (BTA) were prepared by a spray-drying technique using carboxymethylcellulose (CMC-Na) as encapsulating material. The resulting microspheres were characterized by FTIR, TGA, SEM and TEM analysis. Microspheres containing BTA have an average diameter of 1.1 μm. FTIR analysis confir...

Epoxy based composites filled with RhB-loaded TiO2 containers were prepared. SEM, EDX mapping, and Raman spectroscopy showed a uniform distribution of the TiO2 particles in the polymeric matrix. The sensitivity of the composites to UV irradiation was studied. Efficiency of the composite decolorization was found to depend on the amount of RhB-loaded...

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 studi...

The advantage of using magnesium alloys over traditional metals, biodegradable polymer and ceramics lies on their superior mechanical properties and their biocompatibility and biodegradability. This advantage makes them suitable for biomedical applications but prone to corrosion, therefore their biggest advantage is simultaneously a challenge. Magn...

Novel gemini surfactants functionalised with oxygen atom and ester groups were synthesized and characterised by NMR methods. The corrosion inhibiting properties of the synthesized compounds were investigated by potentiodynamic polarization, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). The results show that...

Nanomaterials and a wide-range of biocides have been regarded as emerging contaminants receiving a remarkable scientific attention in the last decade, particularly in terms of their sub-cellular effects. Biomarkers of effect indicate an early biochemical response that has occurred following exposure of an organism to a contaminant. Oxidative str...

The successful preparation of the titania nanotubular layers (TNT) in different deep eutectic solvent based electrolytes was performed in the current work. Choline chloride based deep eutectic solvents with various hydrogen bond donors, such as ethylene glycol, urea and malonic acid were used. All results were compared with standard ethylene glycol...

The specific microstructure of aluminum alloys is herein explored to grow spatially-resolved layered double hydroxide (SR-LDH) clusters on their surface. Upon chemical modification of LDHs via intercalation, adsorption and grafting with different functional molecules, novel surface-engineered surfaces were obtained. Crystal structure and phase comp...

Biofouling is one of the most challenging problems for the maritime industry that has been minimized through the application of coatings containing anti-fouling (AF) biocides (e.g. Cu-based compounds; DCOIT) in immersed structures. An innovative eco-friendly approach based on the encapsulation of AF biocides in engineered nanomaterials (e.g. silica...

It is presented a straightforward procedure based on the CLAYFF force field to perform molecular dynamics (MD) computer simulations with the GROMACS open source package of layered double hydroxide (LDH) materials with different intercalated anions. This procedure enables running very long simulations of systems where all atomic positions are allowe...

In this work active corrosion protection of AA2024 by a bilayer system consisting of a LDH (layered double hydroxides) conversion layer coated by a sol-gel film was studied. Impedance and Scanning vibrating electrode technique (SVET) studies demonstrated an efficient active corrosion protection and self-healing abilities of the systems containing L...

For the application of Mg alloys corrosion is mostly a challenge. Therefore, the early detection of corrosion for Mg based materials is important for automobile and aeronautic industry. The work introduces sensing coatings for metallic corrosion detection at an early stage that will help to mitigate the costs of corrosion through continuous monitor...

Saponins are amphiphilic glycosides present in a wide variety of plants as well as marine organisms. Saponins reduce plant palatability and display fungicide, antimicrobial and insecticide properties. Plant saponins are accepted as safe food, feedstuff and cosmetic ingredient. Notably, saponins extracted from Quillaja saponaria bark are commerciali...

It is critical for the aeronautical industry that the next generation of smart coatings allows the early detection and continuous monitoring of corrosion. Once corrosion is detected, preventive actions can be taken in order to mitigate its costs. Our strategy relies on functional coatings capable of detecting metallic corrosion early on. After appr...

It is critical for the aeronautical industry that the next generation of smart coatings allows the early detection and continuous monitoring of corrosion. Once corrosion is detected, preventive actions can be taken in order to mitigate its costs. Our strategy relies on functional coatings capable of detecting metallic corrosion early on. After appr...

The compatibility between nanocontainers and coating formulations is perhaps the last frontier in the quest for functional coatings. Sensing coatings for early metallic corrosion detection is an urgently needed technology by aeronautical companies to mitigate the costs of corrosion through continuous monitoring. In this work, we revisit phenolphtha...

In the current paper the corrosion inhibition synergy between Ce³⁺ loaded NaY-zeolite (NaY-Ce) and 2-Mercaptobenzothiazole (MBT) loaded Zn-Al layered double hydroxide (LDH-MBT) containers is presented. Solutions and water-borne epoxy coatings containing different ratios of the two loaded carriers were prepared and their protection of AA2024-T3 and...

The application of nano-structured compounds has been increasing rapidly in recent years, in several fields. The use of engineered nano-materials as carriers of antifouling compounds is just beginning and already reveals clear advantages compared to bulk active compounds, such as slowed and controlled release, novel functionality, and high loading...

This work suggests a low-temperature sealing approach for tartaric–sulfuric acid (TSA) anodized AA2024 based on hierarchically organized Li–Al-layered double hydroxide (LDH) structures. The new proposed sealing is expected to be directly competitive to the standard hot water sealing (HWS) approaches because of its reduced treatment temperature and...

Due to their unique electronic and optical features, gold nanoparticles (AuNP) have received a great deal of attention for application in different fields such as catalysis, electronics, and biomedicine. The large-volume manufacturing predicted for future decades and the inevitable release of these substances into the environment necessitated an as...

In this work bleached E. globulus kraft pulp was doped with polyhexamethylene biguanide (PHMB) from an aqueous solution or from suspension of encapsulated silica capsules (PHMB@silica) by impregnation under atmospheric or ultra-high pressure (UHP) conditions (500 MPa). The antimicrobial properties of pulps were evaluated towards gram-negative E. co...

Energy transfer reactions are the key for living open systems, biological chemical networking and development of life inspired nanoscale machineries. It is a challenge to find simple reliable synthetic chemical networks providing a localization of the time dependent flux of matter. In this paper we look to photocatalytic reaction on TiO2 from diffe...

Biofouling is a global problem that affects virtually all the immersed structures. Currently, several novel environmentally friendly approaches are being tested worldwide to decrease the toxicity of biocides in non-fouling species, such as the encapsulation/immobilization of commercially available biocides, in order to achieve control over the leac...