Report on the outcomes of a Short-Term Scientific Mission

Action number: COST Action CA21101 – CONFINED MOLECULAR SYSTEMS: FROM A NEW GENERATION OF MATERIALS TO THE STARS (COSY)

Applicant name: Abdulkadir Sezai SARAC

Details of the STSM

Title: Advanced Characterizations of Magnetic Metal Nanoparticles Containing Biocompatible Polyacrylonitrile Nanofibers.

Start and end date: 29/09/2023 to 08/10 /2023

Description of the work carried out during the STSM

Host Inst: Faculty of Physics, Physics of Functional Materials, University of Vienna, Vienna, Austria (Prof.Wilfried Schranz /e-mail:)
https://ufind.univie.ac.at/de/person.html?id=5054
Electrospinning exhibits the unique ability to produce diverse forms of polymeric fibrous assemblies. The remarkable specific surface area and high porosity make electrospun nanomaterials highly attractive to ultrasensitive sensors and increase their importance in other nanotechnological applications. In terms of production, the specific polymer types, that is, electrospinnable polymers, polymer blends, solution and processing parameters, significantly affect the fiber morphology. Adding carefully selected materials to polymer fiber blends can enhance their properties and make them suitable for a wider range of applications, including energy.
In Medical Magnetic Particle Imaging (MPI), magnetic nanoparticle contrast agents are used that are safer than iodine with high contrast and better sensitivity. Among them, the iron oxide nanoparticle tracers are one of the most preferred for MPI. Magnetic nanoparticles have been studied extensively for biomedical applications. i.e. hyperthermia for the thermal treatment of cancer. It is necessary to develop magnetic nanoparticles with high heating efficiency to optimize the influence of the intracellular environment on magnetic behavior and heat generation. Thus, the design of magnetic nanoparticle composite nanofibers might have applications for imaging and magnetic field manipulation.
Fe-based soft magnetic composite polyacrylonitrile (PAN) nanofibers might considerably improve the magnetic characteristics compared to the traditional bulk metals with large crystals, due to their good thermal and mechanical stability [1]. By the application to various magnetic components for electronic devices, lighter and more compact designs can be generated for current and power transformers, inductors, and current sensors.
Combinations of the composing units of such nanocomposites with the inclusion of magnetic metal nanoparticles (MGMNPs) in biocompatible polyacrylonitrile (known as technical textile material) will increase the efficient electron transport, where we aim to understand the molecular interaction of MGMNPs with polyacrylonitrile structure by advanced characterization methods. Composite Textile materials can be used to create a wide range of sensors, including humidity sensors, strain sensors, and temperature sensors. They can be integrated with other materials, such as conductive polymers and nanomaterials, to create sensors with enhanced sensitivity and selectivity.[2].
Iron oxide nanoparticles provide electrical networks allowing fast and efficient electron transport when these composites are used as anode materials. H atom binds to the surface of O in the not-blocked site and forms a hydrogen bond to the other symmetrically equivalent O atom reported according to the results of the STM measurements [3]. Iron oxide nanoparticles are a promising material for use as anode materials in batteries and other energy storage devices. Polymer fiber blends offer several advantages over traditional anode materials, including high energy density, fast electron transport, and high power delivery, which make them ideal for applications such as electric vehicles.
Embedding magnetic metal nanoparticles (MGMNPs) in biocompatible polyacrylonitrile (PAN) nanocomposite fibers will enhance electron transport and enable soft-surface sensing for breathability, drug delivery, humidity sensing, and electro-active nanofibrous sensors in automotive and aeronautic applications.
This study highlights the mechanical and magnetic properties and applicability of confined magnetic nanoparticles in polyacrylonitrile nanofiber matrix by focusing on their intrinsic properties and assessing the ability of novel engineered functional nanocomposites.[1] Gumrukcu S., Soprunyuk V., Sarac B., Yüce E., Eckert J., Sarac A.S.,” Electrospun polyacrylonitrile/2-(acryloyloxy) ethyl ferrocenecarboxylate polymer blend nanofibers” Mol. Syst. Des.
Eng., (2021)6, 476-492

[2] Huner K., Sarac B., Yüce E., Rezvan A., Micusik M., Omastova M., Eckert J., Sarac AS, Iron oxide–poly (m-anthranilic acid)–poly (ε-caprolactone) electrospun composite nanofibers: fabrication and properties, Molec.Syst. Des. & Eng.(2023)8,394-406

[3] 1G. S. Parkinson,Surface Sci.Reports (2016)71,272-365

Description of the STSM main achievements and planned follow-up activities

At the Host Institute of Faculty of Physics, Physics of Functional Materials, University of Vienna, Vienna, Austria (Prof. Wilfried Schranz), we gained access to thermomechanical and dynamic measurement techniques under a magnetic field, which are not available at our institute. This successful STSM for specific measurements allowed us to develop a long-lasting collaboration with the Host institution.

For this STSM project, three different compositions of nanocomposites, i.e., iron oxide and Mn ZnFerrite nanoparticles containing nanofibers of polyacrylonitrile and pure polyacrylonitrile nanofibers without magnetic nanoparticles are fabricated at home institution (Istanbul Technical University-ITU) by electrospinning technique. In the Host laboratory, thermomechanical measurements and thermomechanical measurements under a magnetic field are performed. In Erich Schmid Institute of Materials Science ( ESI): HRSEM, XRD measurements are realized.

Electrochemical measurements including electrochemical Impedance Spectroscopic (EIS) characterization will be performed at the home institute (ITU). The simulation of the EIS data will be conducted with a proper electrical equivalent circuit using the ZSimpWin V.3.10 analysis program.

We obtained detailed experimental data on the properties of polymeric composite nanofibers with magnetic nanoparticles in a wide range of temperatures under thermomechanical and dynamic measurements under a magnetic field using electrospun Fe-based polyacrylonitrile composite nanofibers obtained at Istanbul Technical University. Further characterizations are performed using high-resolution SEM and XRD at the Erich Schmid Institute of Materials Science (ESI). In this STSM study, we have examined the effects of static magnetic fields (SMF; 120 mT [Bmax] on the Dynamic mechanical analysis (DMA) used to measure the temperature dependencies.

All samples showed distinct changes in the glass transition (Tg) (around 370 K) and stiffening (around 600 K) regions (Fig.1). Before the glass transition, the sample stiffens due to interactions between magnetic nanoparticles as the PAN matrix with nanoparticles. Also, in the Mn-Zn-ferrite sample, we observe a significant shift of Tx in the stiffening region (around 600 K) when the magnetic field (120 mT) is applied.

The observation of a significant shift of the glass transition to the region of high temperatures when a magnetic field is applied in the Mn-Zn-ferrite sample is also an interesting result. It suggests that the magnetic field has a strong influence on the dynamics of the glass transition. The two peaks in tanΘ with corresponding two distinct changes in the storage modulus in the region of glass transition probably correspond to two relaxation processes. The first relaxation is the glass transition of the PAN matrix. The second one corresponds to the glass transition of the PAN matrix around nanoparticles, where the relaxation processes slow down due to the contact of the PAN matrix with nanoparticles.

The significant shift of crystallization temperature (Tx) in the stiffening region when the magnetic field is applied in the Mn-Zn-ferrite sample suggests that the magnetic field also affects the dynamics of the stiffening process. The stiffening process is thought to be associated with the interaction between the PAN matrix chains. The magnetic field may affect the dynamics of the interaction with PAN matrix chains. Overall, the results suggest that the magnetic field has a strong influence on the dynamics of the glass transition and the stiffening process in the Mn- Zn-ferrite sample. This new finding could have implications for the design and development of new materials with improved properties.

A possible explanation for the observed effect is that the magnetic field may align the magnetic moments of the Mn-Zn-ferrite nanoparticles, which could lead to a change in the interactions between the nanoparticles and the PAN matrix. This could affect the dynamics of the PAN matrix chains and the glass transition temperature. The results of this study provide a new insight into the influence of magnetic fields on the dynamics of glass transition and stiffening in Mn-Zn-ferrite sample.

Fig.1. Storage (Y’),Loss Modulus(Y’’),Loss factor (tan d) vs. Temperature for the PAN, Fe2O3/PAN, MnZnFerrite /PAN Nanofiber (Above DMA experiment of Fe2O3/PAN NF, before and after )

SEM results showing homogeneous nanofiber formation and nanoparticle and partially cluster distribution(Fig.2) , especially high magnification indicate that the sample is well-dispersed and has a uniform nanofiber morphology. This is a desirable outcome for many nanofiber-based applications, such as filtration, drug delivery, and tissue engineering.

Iron oxide nanoparticles in small sizes exhibit supermagnetic properties. The magnetic moment of iron oxide nanoparticles can be increased and the surface of ferrite nanoparticles can be modified by  polymers to increase their stability in solution.

Fig.2. SEM images of PAN (a), Fe2O3/PAN (b), MnZnFerrite/PAN Nanofibers

The scientific goals of the STSM will contribute to both the general goals of COSY and the specific objectives for this grant period. The study will especially contribute to COSY WG3 “Confined Metal and Metal-Oxide Nanoparticles” through the synthesis and characterization of nanofibers of magnetic metal oxide nanoparticles with biocompatible polyacrylonitrile nanofibers. This STSM study investigated the thermomechanical properties of magnetic nanoparticle-embedded polyacrylonitrile (MNPs-PAN) nanofibers across a wide temperature range in a magnetic field. Additional spectroscopic(XPS, Raman), electrochemical(CV, EIS), and morphological characterizations will be performed to elucidate the molecular interactions and properties of MNPs-PAN nanofibers.

We will disseminate the research results to the public through international peer-reviewed publications with acknowledgment of COST COSY. We have planned efforts among ITU and Univ. Vienna, integrate experimental and theoretical knowledge in further collaborations.

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