Project Title: Structural investigations of functionalized mesoporous silica by means of small angle neutron scattering and other methods
Project Manager, from Romania:Dr. Putz Ana-Maria,Institutul de Chimie “Coriolan Drăgulescu”, Timisoara, Romania
Project Manager, from JINR (Joint Institute for Nuclear Research): Dr. Kuklin I. Alexander, Frank Laboratory of Neutron Physics, Dubna, Rusia
Total value of the Project: 4500 USD (IUCN+ICT)/2018;12000 USD(IUCN+ICT)/2018-2020
Eligible value JINR: 2600 USD/2018; 6500 USD/2018-2020
Eligible value ICT: 1900 USD/2018; 5500 USD/2018-2020
Duration of Contract: 3 years (2018-2020)
The Funding Entity: Ministry of Research and Innovation
Type of the project: Cooperation Project between
JINR-Joint Institute for Nuclear Research (IUCN-Institutul Unificat de Cercetări Nucleare) Dubna, Russia,
and the Institutes from Romanian (with the support of the Romania-JINR Committee, consultative body of the Ministry of Research and Innovation).
Project Details: Institutul Unificat de Cercetări Nucleare (IUCN):
IUCN Theme Members: Dr.Dmytro Soloviov, Dr. Oleksandr Ivankov, Dr. Andrey Rogachev, Dr. Maria Balasoiu
ICT Theme Members: Dr.Cecilia Savii, Dr. Catălin Ianăşi, Drd. Roxana Nicola, Chim. Elena-Mirela Picioruş.
Abstract: It comes the necessity in preparation and characterization of new porous materials with tailored properties that can be used for applications like drug delivery and water pollutants adsorbents. The project intends to develop functionalized mesoporous silica by employing different templates, cationic surfactants and ionic liquids, and different functionalized precursors for the mesoporous silica. Beside the basic classical investigation methods, we use SANS as an advanced technique, essential for structural characterization of new synthesized materials. Concerning the estimated results, we are expect to obtained new materials with good properties as water pollutant adsorbents for the environmental remediation and also new drug delivery systems with good loading capacity and controlled release regime.
Objectives:
1. The sol-gel synthesis, including the sonocatalysed synthesis, by using different synthesis variables;
2. The surface functionalization of selected samples, via the covalent bonding, by using one of the following organic groups -NH2, COOH–, SH–.
3. The structural and morphologic studies of obtained materials by using: general material investigation techniques (TGA, FT-IR, XRD, nitrogen adsorption-desorption) and by using specific nanomaterial’s investigation techniques: SANS, SAXS, electron microscopy (TEM);
4.The evaluation of the efficiency as: carriers, in drug delivery systems (the drug loading/release tests) and as water pollutant adsorbents, for the environment remediation.
Results:
For the first year of project (2018) we performed the synthesis of new materials, by varying the amount of methoxyethanol.Silica samples were prepared by using the sol-gel synthesis, using CTAB, TEOS in ethanol and/or 2-methoxyethanol – water mixtures, and base catalyst NH3. We have used the Alcohol:H2O molar ratio=1:10. Ethanol was used for the first sample and it was progressively substituted with 2-methoxyethanol, for the next samples from the series. The syntheses were performed at room temperature for the first series of synthesis and the synthesis were performed at 50°C, for the second series of samples. The type IV b isotherm (specific for mesoporous materials of smaller width and conical or cylindrical shape) was obtained for all the samples. The presence of narrow hysteresis in the interval 0.2-0.4 P/Po suggests that some wide pore could have more access to external surface. The data extracted from isotherm show that the biggest specific surface area was obtained for sample synthetized only with ethanol (1793 m2/g). By substituting the ethanol with 2-methoxyethanol, a small decrease of the specific surface area can be observed. The results indicate a narrow distribution of the pore size with a mean value of 3.5 nm for all the samples. Using BJH model, a small increase in pore size was observed from 3.0 nm to 3.3 nm, with the increase of 2-methoxyethanol concentration. The total pore volume of samples is increasing, by the substitution with 2-methoxyethanol. The same trend can be observed for the materials synthetized at 50oC. The isotherms are type IVb presenting also a narrow hysteresis. The surface area decreases when the substitution with 2-methoxyethanol is progressively made. For the second series of samples, the pore size distribution is more compact, by presenting very few changes in structure. The total pore volume has the tendency to increase also when ethanol was replaced. The SAXS results demonstrated that ordered structure were obtained, and together with high specific surfaces area, suitable characteristic for our envisaged applications, like drug delivery systems, have been obtained.
