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Ongoing Projects
Tailoring colloids through supramolecular interactions: from fundamentals to applications
This project aims at achieving controlled association of varied colloids through either hydrophobic, electrostatic, or covalent bonds (or their combination) to tailor their characteristics, preferably in a reversible fashion. The envisaged functional colloidal objects span from surfactant and/or polymer aggregates, to nanoparticles of inorganic nature (mostly silica) or derived from renewable nanomaterials such as nanocelluloses, nanolignins, and nanochitins. The processes to be investigated include the preparation of polymer/surfactant aggregates for encapsulation of biomolecules and model drugs, preparation of nanomaterials under confinement, rheological control of fluids, model systems for bioactive materials, responsive polymers, and multiscale association materials. In summary, we are proposing a series of studies to be jointly developed by a group of researchers of wide expertise, with the common focus on understanding how colloidal systems may be tailored to achieve new properties and functionalities. Funding: FAPESP (Thematic Research Grant)
Combining the versatility of lyotropic liquid crystals with mechanical properties of nanocelluloses - relationship between microstructure and macroscopic properties
Cellulose-based nanomaterials have been widely studied for applications in different types of formulations, given their abundance, sustainability, ease of obtaining and versatility, especially in terms of mechanical properties. These formulations commonly contain surfactants in their compositions, molecules that offer the system characteristics such as foamability, high viscosity, detergency, and wettability. These surfactants self-assemble, in solution, forming liquid-crystalline phases, such as lamellar, creating new possibilities for targeted applications. Although both systems are investigated separately, information about their modes of interaction and, consequently, the properties resulting from their combinations, are few explored. This proposal aims to investigate the interaction of cellulosic nanomaterials in suspension, such as nanocrystals and nanofibers, with lamellar phases formed by surfactants, combining the properties of both components to obtain complex fluids, such as liquid crystals, dispersions of (nano)particles and hydrogels, with high performance and potential applications in the cosmetic, lubricant and surface cleaning areas. For this, the proposal will have a multi-institutional team formed by specialists both in obtaining and applying cellulosic nanomaterials and in the study of colloidal systems formed by association of surfactants. The study will be based on different experimental characterization techniques, such as electron microscopy, rheology, 1D and 2D nuclear magnetic resonance, and light and X-ray scattering, in order to obtain information at the molecular level, and thus, to correlate the microstructure of the systems with the resulting macroscopic properties, thus promoting the formulation of new products with a sustainable character and with improved properties.. Funding: CNPq (Universal Research Grant)
Polymeric fibers as drying additives for refractory castables
Funding: Private company (confidential)
Dispersion of cellulose nanocrystals in aqueous media
In order to produce stable and processable cellulose nanocrystals (CNCs), fundamental understanding of the relationship between the surface chemistry, interaction forces and colloidal stability of CNCs is necessary. We will develop analytical tools for the quantification of interaction forces, macroscopic evaluation of the stability of CNCs, and chemical modification of CNCs. By careful analysis of the structural-property relationship between the surface properties of CNCs and their interactions in aqueous solution, critical factors controlling the stability of CNCs will be identified. Based on this knowledge, we will develop protocols for the manufacture of stable CNCs. We will also evaluate and elucidate the impact of additives on the colloidal stability of CNCs. The impact of drying and modes of removal of hydration water on the dispersibility of CNC in water will be examined. The role of functionalization of CNC with oligomers or polymers on the colloidal stability of CNCs will be pursued. The dual purposes of functionalization are to introduce electrostatic and steric stabilization to the CNC. Strategies to perform such modification within the current manufacturing process would be explored. Functionalization not only enhances the stability of CNCs, but it can also be used to impart new properties and functionalities that may be critical for CNC incorporation in product formulations. It is hoped that this research will advance our understanding of the behaviour of CNC in aqueous solution that will enhance the application and use of CNC in new applications. We will further conduct a comprehensive study of several factors known or believed to influence agglomerate formation in aqueous dispersions, and to examine the effects of varying multiple factors simultaneously. We will study the process and kinetics of CNC agglomeration under various conditions, but primarily focused on those present in the final stages of CNC manufacturing. Such scientific knowledge and development will be relevant to our industrial partners in Canada (CelluForce Inc.), and in Brazil (Suzano & Fibria). Funding: FAPESP (SPRINT) & Consortium of Alberta, Laval, Dalhousie and Ottawa (CALDO)
The project Nature4Health proposes to develop innovative biomaterials conjugating natural resources, namely agro-food product (VCO) and marine-origin polymers (CHT), by designing 2D (films) and 3D-based structures (oleogels, sponges) as high added-value wound care materials. Thanks to the intrinsic nature of active components, the produced matrices can be used to accelerate the healing of acute superficial (wound dressings) and chronic wounds (oleogels), without the need for additional antibiotics and anti-inflammatory agents. The repercussions of these products can be tremendous, not only from the economic point of view but also from the environmental ones, since they are obtained in a sustainable way and will be processed using green chemistry methodologies. In UMINHO, the 3Bs Research Group is a worldwide group recognized by the development of novel biomaterials (hydrogels, scaffolds, membranes, nano/microparticles) based on natural polymers for applications in drug delivery and tissue engineering of bone, cartilage and skin. This is accomplished by developing several isolation/purification tools and processing methods, allowing the fabrication of integrated biomaterials. Particularly, the IR of this project is a well-known researcher on chitin/chitosan as biomaterials. Her findings had contributed to enhancing the knowledge on marine-based systems for soft tissue regeneration. Therefore, the large experience of the Portuguese team on polymer processing and characterization will cover different aspects of the proposal. The expertise of Brazilian team, UNICAMP, is based on thermodynamics and various aspects of colloid and interface science, including polymer/surfactant solutions, association with nanoparticles such as metallic ones or nanocrystalline cellulose, many aspects of phase equilibria, including petroleum samples and elucidation of structures in these complex fluids. For this purpose, the Brazilian group has developed expertise in techniques such as different calorimetric techniques for studies on the energetics of these interactions and structural ones such as dynamic and static light scattering, SAXS or rheological measurements. Then, the partnership of the Brazilian team will be crucial for the achievement of the Nature4Health project. Funding: FAPESP & Fundação para a Ciência e a Tecnologia (FCT, Portugal)
Use of bacterial nanocellulose in water-soluble edible polymer matrices
The use of cellulosic structures at the nanoscale has been investigated because of its advantages (e.g., larger specific surface areas) over larger counterparts, thus contributing to more promising applications in rheology control in colloidal systems. The main routes of obtaining nanocellulose involve the exploitation of plant resources; however, some bacteria are capable of producing cellulose, which, like those of vegetal origin, serve as a source for obtaining nanofibers and nanocrystals. Thus, the objective of this project is to study the modification of the rheological behavior of colloidal systems containing water and water-soluble polymers (alginate, gelatin, hydroxypropyl methylcellulose and pectin). The study will allow obtaining a better polymer matrix composition to be applied as a potential substitute for non-biodegradable materials suitable for single-use plastics, such as packaging, with potential in edible packaging. This project is expected to promote advances in solution characterization and interactional knowledge in colloidal systems composed of nanocellulose and biopolymers so that the study enables new applications of the obtained materials. Funding: FAPESP (Regular Research Grant)
Biodegradable films from bulk fruit processing byproducts
The proposal involves the production of biodegradable films with active (antioxidant, antimicrobial and/or UV absorber) properties from bulk fruit processing byproducts. The first step will be to analyze the chemical composition and to make preliminary tests on processing byproducts from orange, passion fruit, pineapple, mango, and banana (as well as on their mixtures). At least four byproducts and/or mixtures will be selected for the further steps. After drying and milling, the byproducts will be subjected to four alternative pretreatments (including acid, alkaline, and thermal treatments) to avoid film cracking resulting from undesirable interactions between components. The chemical changes resulting from each pretreatment will be studied. After the pretreatments, the dispersions will be submitted to degassing and batch casting. The films will be characterized in terms of tensile, thermal and optical properties, water vapor barrier, water solubility, antioxidant and antimicrobial activities, as well as ultrastructure and interactions between components. If necessary, adjustments on the tensile properties will made by using plasticizers and/or reinforcing agents. Selected byproducts and/or mixtures will be submitted to continuous casting (simulating pilot scale). The film properties (especially the tensile ones) will be compared to those of low-density polyethylene, in order to evaluate their relative performance and prospection of applications. Funding: FAPESP (Regular Research Grant)
Passive-sustainable climate-control strategies in a tropical climate using digital fabrication
This project aims at developing passive climate-control products based on phase-change materials and shading systems that can make light-weight construction perform better in tropical climates. This can lead to buildings with a lower carbon footprint both in terms of construction and operation. Funding: CAPES/DAAD (PROBRAL)
Banana snacks as vehicles for probiotics
Considerando a grande demanda por produtos que atendam aos requisitos de saudabilidade e conveniência, propõe-se o desenvolvimento de formulações de dois tipos de snacks probióticos de banana, a saber: um flexível e gomoso (fitas comestíveis) e outro quebradiço e crocante (banana liofilizada com revestimento probiótico). Espera-se que os snacks protejam os probióticos contra degradação durante o processamento, a estocagem e a passagem pelo estômago, mas permitindo sua liberação no intestino. Na primeira etapa, serão desenvolvidas as fitas, para as quais serão testadas duas matrizes polissacarídicas (celulose bacteriana e amido, respectivamente não-digerível e digerível) e duas cepas probióticas (Bacillus coagulans e Lactobacillus casei, respectivamente esporogênica e não-esporogênica), além da presença ou ausência de prebióticos (frutooligossacarídeos – FOS). As diferentes formulações serão avaliadas em termos de propriedades físicas (propriedades mecânicas, térmicas, óticas e estruturais) e desempenho funcional (capacidade de manter o desempenho probiótico ao longo do trato gastrointestinal e estabilidade da cepa probiótica durante a estocagem). A formulação com melhor combinação de propriedades físicas e desempenho funcional será ainda produzida por casting contínuo (como forma de propor um aumento de escala para o processo) e submetida a testes de aceitação sensorial. Na segunda etapa, a formulação escolhida para as fitas será adaptada (sem polpa de banana) para revestir fatias de banana, que serão liofilizadas . As fatias liofilizadas serão submetidas a testes de estabilidade ao longo da estocagem (variação de massa, textura, cor e estabilidade da cepa probiótica) e avaliação de aceitação sensorial. Funding: CNPq (Universal Research Grant)