Development of smart magnetic-field responsive fluids based on surfactant binary mixtures

Project leaders

Pietro Calandra, Mikolaj Pochylski

Agreement

POLONIA - PAS (NUOVO ACCORDO) - Polish Academy of Sciences/Polska Akademia Nauk

Call

CNR-PAN 2017-2019

Department

Chemical sciences and materials technology

Thematic area

Chemical sciences and materials technology

Status of the project

New

Research proposal

Surfactants are amphiphilic molecules that possess, within their molecular architecture, both polar (hydrophilic) and apolar (hydrophobic) moieties. In the past, they have been always used as solute in suitable solvents in many fields: detergency, emulsification, lubrication or nanoparticle synthesis. However, it has been recently developed an innovative approach (see Italian Principal Investigator's scientific production) to use BINARY mixtures of two PURE liquid surfactants, with no solvent. The absence of any solvent maximizes the surfactant concentration, therefore the merits of the system, deriving from the presence of the two surfactants, are obviously driven to their extreme. The proof for the effectiveness of this strategy is the recent preparation of surfactant-based liquid mixtures with striking properties as enhanced proton conductivity, anomalous 1D diffusion, anti-Arrhenian behavior of proton conductivity [P. Calandra et al. Langmuir, 2013, 29(48), 14848-14854; P. Calandra et al. J. Coll Interf Sci, 2012, 367, 280-285; P. Calandra et al. J. Mater Chem C, 2015, 3(13), 3198-3210]. The state of the art in this field is represented by the recent preparation of fluids with extreme magnetic field-response in optical birefringence [M. Pochlyskj et al. RSC ADVANCES, 2016, 6(32), 26696-26708]. The scientific clue below the preparation of such materials is novel: since the delicate equilibrium among polar-polar, polar-apolar and apolar-apolar interactions involving the two molecules dictates the local and long range intermolecular self-assembly, it is possible to have a composition-dependent local nano-segregation with formation of aggregates at the nanoscale which can be oriented by a magnetic field thus giving birefrincence. This is an unprecedented way to induce optical birefringence by means of a magnetic field.
The scientific idea of this project is therefore to exploit the possibility of a local nano-segregation to develop nano-demixed (demixed at the nano-scale) stable binary mixtures of surfactants. The aim is to understand the physico-chemical principles at the base of local intermolecular assemblies formation and their behaviour under magnetic field including their anysotropy. The theoretical clues will be exploited to design smart fluids which can respond to a magnetic field by a change in their optical birefringence for specific application. The materials are cheap and the procedure of preparation is cost-effective, simple and fast and these factors constitute added value. Here is the plan: various alkylamines/alkylphosphates binary mixtures will be prepared at different alkylamines/alkylphosphates ratios. Different alkylamine (from C4 to C24) and different alkylphosphates, (from C3 to C16) will be used to explore the effect of the alkyl chain length. The structure (intermolecular, short and medium-range) and the property (birefringence) of each system will be investigated through various techniques: UV-Vis and fluorescence spectroscopy, Raman Scattering, X-Ray scattering, Dynamic light scattering, Brillouin scattering and Magnetically induced linear birefringence.
The two partners, due to their specific competencies, will carry out strictly complementary jobs:
(i) The Italian team has a consolidated experience in the preparation of surfactant-based liquid mixtures and their study through NMR, Raman, X-ray scattering, conductimetry, rheology, dielectric spectroscopy (see P. Calandra -Italian principal investigator- scientific production). They will be involved in the preparation of the surfactant mixtures and in their characterization by Raman scattering (T. de Caro), UV-Vis spectroscopy (R. Toro) and fluorescence spectroscopy (D. Caschera), X-RAy Scattering (Valeria la Parola).
(ii) The Polish team has a good expertise in the optical characterization of liquids, mixtures, suspensions and liquid crystals (M. Pochylski, J. Gapinski). The Polish Principal Investigator has a long experience in the optical studies of fluids using light scattering and magnetic birefringence methods, as well as a deep skill in the piloted design of instruments for the optical characterization (see M. Pochylski - Polish principal investigator - literature). They will be responsible for the optical characterization of the samples
As it can be seen, the specificity and complementarity of the skills of all the researchers involved render this cooperation necessary.
All the collaborators of the Polish group are young (average age 35) as well as the Italians (mostly 40). In particular the PhD students Agnieszka Polatynska M.Sc. and Kamila Ciezar M.Sc., thanks to their hard-working attitude, are also involved. They are expected to learn a lot from this work.
Both partners desire this cooperation to become part of a wider network of people and institutions (University of Calabria, University of Palermo, IPCF-CNR, Adam Mickiewicz University in Poznan) already working on advanced "soft" materials. This project would allow to establish the scientific and human feeling necessary for this.
The results are intended to be presented in international conferences, published in ISI-indexed scientific journals or to be included in patents.
The young age of the researchers involved, the motivation to write high-impact articles and the long-term vision to form a compact research group for future funding applications constitute added value of this project.
As for the methodology and the work plan see the year-by-year timetable reported in another section of the online submission.

Research goals

The objective of the present project is the understanding of the physico-chemical principles at the base of local intermolecular assemblies formation and their behaviour under magnetic field in surfactant-based liquid mixtures. The final goal is the exploitation of such theoretical clues to the piloted design, at low cost and with quick/easy procedure, of smart fluids which can respond to a magnetic field by a change in their optical birefringence.
Therefore, at short term (1th - 2th years), the immediate objective is the comprehension of the structure and stability of different surfactant-based as a function of composition and alkyl chain length and their correlation with the behaviour under magnetic field in terms of induced birefringence. To follow this objective it is necessary to understand the intermolecular interactions involved, and this will be achieved through the synergic work of the Italian and Polish team whose skills are complementary.
The long-term (2th - 3th years) objective is to exploit the know-how acquired to optimize the properties of these systems and to maximize their performances by finding the best combination of alkylamines and alkylphosphates.

Last update: 16/04/2024