1. Briefs about your research. The application of photocatalytic processes to buildings surfaces began in the early 1990s, and t...
1. Briefs about your research.
The application of photocatalytic processes to buildings surfaces began
in the early 1990s, and this technology developed rapidly with construction
materials, such as ceramic tiles, paving-blocks, glass, paints, and concrete
pavements, besides in finishing and coatings for air-water purification. TiO2
nanoparticles have attracted much attention as photo-functional materials for
self-cleaning, antifogging, self-sterilizing, and antibacterial effects
attracting many industrial interests due to the advantages of using these
particles in building materials. This electrochemical process accelerates the
oxide reduction reactions of organic compounds by the incidence of solar
radiation. This technique creates self-cleaning surfaces that neutralize the
effects of environmentally polluting substances. The external surfaces of
buildings as paints and inorganic coatings when containing a photocatalyst
material could provide a surface with hydrophilic characteristics decreasing
the degree of dirtiness on these surfaces. These facades could be washed by the
rain orwater spray, promoting a self-cleaning effect. Thus, heterogeneous
photocatalysis has also opened up opportunities not only in studies about
environment decontamination but also for producing self-cleaning materials.
This research is part of the Ph.D. thesis conducted to evaluate the
influence of the granulometric and morphological distribution of n-TiO2
particles in the properties of coating mortars. The photocatalytic process is
influenced by several factors, such as the mortar characteristics, the
proportion of the components of the mixtures, n-TiO2 mixing
procedure, physical/chemical (morphology) characteristics of n-TiO2
and the application procedure on a subtract. The n-TiO2 content
added to the cementitious materials to activate the photocatalytic process and
the photoinduced superhydrophilicity phenomenon, through the activation of the
n-TiO2 semiconductor, has already been discussed by many authors.
Conclusive results with different n-TiO2 content were already
discussed in various studies. However, the procedures used for addition to
cement mixing, as well as the application on the substrates, are still subject
to several investigations.
The research was done based on results obtained in previous studies of
the author - The effectiveness of TiO2additions to mortar to maintain initial
conditions in terms of its reflectance to solar radiation(https://doi.org/10.1590/s1678-86212017000300161.)and guided
the methods and proportions used to produce thenew mixtures.The results of
reflectance to solar radiation and color perception were already obtained in
the evaluation of the different n-TiO2 contents added to the coating
mortars are presented inthe paper - Photocatalytic Performance of White Cement Mortars Exposed in UrbanAtmosphere (https://globaljournals.org/GJRE_Volume19/1-Photocatalytic-Performance-of-White.pdf).In this study, it was observed that the
higher content of fines added to the mortar mixtures presented problems
regardingthe workability. The higher water content added resulted in a higher
porosity. Besides, it was also observed a high drying shrinkage in the mortars
during the initial months of exposure in the urban environment that affectedseverely
the performance of mortars.The results obtained showed the need for better
characterization of the fresh and hardened state of the mortars besides
studying theeffect of the addition of polypropylene microfibers to the
mixtures, to reduce the drying shrinkage.
Tests were carried out to evaluate
the dispersion of the polypropylene microfiber in the mixtures. The addition of
these microfibers aims to avoid the drying shrinkage effect that commonly
occurs with the coatings during their cure to the hardened state. It was tested
to add the polypropylene microfibers to the mixtures, before the addition of
the powder material. The tests and the results obtained for each mixture are
presented in - Influence of polypropylene microfibers (PPMF) dispersion
procedure on fresh and hardened rendering mortar properties(http://dx.doi.org/10.1590/s1678-86212020000200384).
The polypropylene microfiber addition studies were done to reduce the
effect of drying shrinkage and showed the importance to study the procedure of
adding and dispersing in kneading water. New blends were produced with the
addition of polypropylene microfiber and n-TiO2 in its cement matrix.
The influence of n-TiO2 addition procedure in the cementitious
matrix in the process of agglomeration, drying shrinkage and other mechanical
properties of mortars were studied. The methods used and the results obtained
for each type of mixture tested is presented in - Influence of the nano-TiO2
dispersion procedure on fresh and hardened rendering mortar properties(https://doi.org/10.1016/j.conbuildmat.2019.04.190).
2. How much time did you spend to complete this work?
3. Who/What inspired you to research on this topic and over what time?
3. Who/What inspired you to research on this topic and over what time?
The interest came during a class of Integrated Urban Sanitation Systems of the master's course in 2014. Since then, the research has been developed studying the potentialities and possibilities of different uses of these nanoparticles in materials and components surfaces. The study is going on towards the presentation of more assertive results in the next two years regarding the procedure for using n-TiO2, which is by addition and/or application and its effects in the reflectance to solar radiation and luminous
4. Any personal experience
or suggestions or ideas for future works in this field?
This study, show there is a large research field for
the use of n-TiO2in cementitious coatings, regarding to its
crystallography, size, dispersion of the nanoparticles, and application
procedure of n-TiO2 in coating mortars.It is of high importance the study
about the
influence of n-TiO2 addition procedure in the cementitious matrix
because the tests showed agglomeration, drying shrinkage and other mechanical
properties on the mortars in the tests. The methods used and the results
obtained for each type of mixture tested is presented in - Influence of the
nano-TiO2 dispersion procedure on fresh and hardened rendering
mortar properties
5. Your publishing
experience with Global Journals (optional).
This was my first
experience with Global Journals and it certainly won't be the last. The whole
team was very solicitous and competent from the beginning of the process until
the publication of the article. So, I don't want to mention names but
congratulate the team as a whole.
7. Short autobiography, a
biography of co-authors and research guide.
Sérgio Roberto Andrade Dantas Graduated in Architecture
and Urbanism from the University Nove de Julho (2002). Specialization in
Buildings: Construction Excellence and Anomalies from Mackenzie University
(2006). Specialization inHistory of Art from FAAP University (2014) and Professional
Master in Housing: Planning and Technology from Technological Research
Institute of the State of São Paulo (2016). He is currently a Ph.D. candidate
in the Department of Civil Construction Engineering by Escola Politécnica of
the University of São Paulo. Experience in civil engineering at construction
processes and project and construction management. Works as a founding partner
of Enjoy Architecture and as a professor of Architecture and Civil Engineering
course. Fields of interest: photocatalysis, nanomaterials,
thermal comfort, energy conversion, colorimetry, mortarsand concretes
reinforced by fiber, constructive system.
Fulvio Vittorino Graduated in Mechanical
Engineering from the University of São Paulo (1988), graduated in Data
Processing Technology from the State Center for Technological Education Paula
Souza (1987), master's degree in Mechanical Engineering from the University of
São Paulo (1994) and a doctorate in Mechanical Engineering by the University of
São Paulo (2001). He is currently a regular professor of specialization courses
at the University of São Paulo. He is a researcher and Director of the
Technological Center for the Built Environment at the Technological Research
Institute of the State of São Paulo. Fields of interest: thermal
performance of buildings, thermal comfort, constructive system, performance
evaluation, and computational performance simulation.
Kai Loh Graduated in Chemistry from the
University of São Paulo (1972), master's and a doctorate in Civil Construction
Engineering from the University of São Paulo in 1992 and 1998 respectively. She
is currently a researcher at the Department of Civil Construction Engineering
at Escola Politécnica from the University of São Paulo. She was a Chemical
Researcher at the Civil Engineering Division of the Technological Research
Institute of the State of São Paulo for 23 years. Coordinator of the Commission
for Paints for Civil Construction (CE-02: 115.29) for 15 years. Works in the
area of Materials and Components of Civil Construction and Sustainable
Construction. Specialist in the field of paints for civil construction, paints
based on lime and cement, studies of cold roofs ("cool roofs"), water
repellents, cold and self-cleaning coatings (photocatalysis), cold pigments,
nanoparticulate materials. It also works in studies with a mortar and concrete
additives, sealants and release agents. Fields of interest: performance,
durability, pathology, sustainability and the environment. 
Roberto Cesar de Oliveira Romano is graduated in Chemistry (1999-2003)
and has a Master's in Material Science and Engineering from the Federal
University of São Carlos (2003-2005). His PhD. was performed at the University
of São Paulo (2008-2012) in Civil Construction Engineering. He has 3
Post-doctoral Research performed from the University of São Paulo (2012-2019).
Currently, is a researcher at the Department of Civil Construction Engineering
at Polytechnical School from the University of São Paulo. Fields of interest: Rheology, Chemistry of cement, Residues,
Additive Manufacturing
