Microstructure and properties of hybrid porous materials

• Grant number: 24/20008-0
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2025
• End date: March 31, 2028
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Denise Freitas Siqueira Petri
• Grantee: Denise Freitas Siqueira Petri
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Three-dimensional porous structures like aerogels, cryogels, and xerogels are interesting due to their low density and high surface area. This proposal focuses on the development of cryogels and xerogels, which have a common starting point in precursor hydrogels, using polysaccharides, kapok fiber (KF) and amphiphilic molecules. KF is a lignocellulosic, hydrophobic, hollow fiber, with an average diameter of 22 ± 2 µm and a wall thickness of ~ 1.0 µm, and little explored in the construction of cryogels or xerogels. Cryogels are obtained from the freezing of hydrogels, followed by sublimation of ice crystals, while xerogels are obtained from the evaporation of water from hydrogels. The main questions we want to answer with this project are how (i) the chemical structure and charge of the polysaccharides and amphiphilic molecules affect the intermolecular interactions between them, in the absence and presence of KF, (ii) the storage modulus G' values of the different precursor gels correlate with the compression modulus (E) values of cryogels obtained by different freezing modes and xerogels, (iii) the microstructure (porosity, pore size distribution) of cryogels and xerogels correlate with acoustic absorption values and of thermal conductivity, (iv) KF modified with negatively charged surfactant can adsorb metallic ions from undergraduate laboratory waste (IQUSP), (v) the microstructure and a possible structural hierarchy affects O2 release from cryogels and xerogels containing CaO2, and (vi) KF affects the formation and stability of liquid foams. (AU)