Stockholms universitet

Ehsan HadiPhH Student

Om mig

Seyed Ehsan Hadi är en tvärvetenskaplig forskare och utbildare med mångsidig kompetens och värdefull erfarenhet inom flera områden, bland annat materialkemi, materialvetenskap och nanoteknik. Han föddes 1993 och disputerar för närvarande i materialkemi under ledning av professor Lennart Bergström vid Stockholms universitet. Han är också knuten till Wallenberg Wood Science Center (WWSC) och Treesearch, två ledande plattformar för forskning och innovation inom den skogsbaserade bioekonomin. Dessförinnan tog han sin masterexamen i materialvetenskap och nanoteknik vid Bilkent University.

Som Senior Graduate Research Assistant vid Stockholms universitet leder Ehsan projekt, utformar experiment, utför laboratoriearbete och analyserar data. Han fungerar också som mentor och utbildare för juniora doktorander, grundutbildade studenter och gymnasieelever och ger vägledning och stöd i deras forskningsprojekt. Med över 6 års erfarenhet av arbete i olika laboratorier och renrum har Ehsan skaffat sig en djup kunskap om flera karaktäriseringsinstrument och elektronmikroskop, vilket gör det möjligt för honom att få högupplösta TEM- och SEM-bilder av nanostrukturer och utföra sofistikerade analyser av nanomaterials fysikalisk-kemiska egenskaper.

Hans starka färdigheter i ledarskap och lagarbete tillsammans med en gedigen bakgrund inom vetenskapliga områden gör att han kan överbrygga klyftan mellan olika discipliner och bidra med nya perspektiv och lösningar på forskningsfrågor. Som utbildare är Ehsan skicklig på att kommunicera komplexa vetenskapliga begrepp till en bred publik, vilket gör honom till en värdefull resurs för alla projekt eller organisationer som kräver ett tvärvetenskapligt tillvägagångssätt för att lösa komplexa problem.

Forskning

Ehsan är en specialistforskare som fokuserar på att undersöka träbaserade nanomaterial för att förstå deras process-struktur-egenskapsrelationer. Hans forskning syftar till att optimera produktionen och tillämpningen av dessa nanomaterial. En stor del av hans arbete innefattar karaktärisering av dispersioner av nanomaterial, inklusive att utveckla nya tekniker för att förbättra de mekaniska, termiska och andra prestandaegenskaperna hos träbaserade nanomaterial.Ehsans övergripande mål är att främja det vetenskapliga samfundets kunskap om multifunktionella, högpresterande träbaserade nanomaterial. Genom innovativa bearbetningsmetoder strävar han efter att utveckla dessa specialiserade material för att låsa upp deras potential för olika industriella och kommersiella tillämpningar. Hans forskning fokuserar på att skapa och tillämpa nya strategier för att ta itu med de komplexa utmaningar som är förknippade med att producera optimerade träbaserade nanomaterial.

Publikationer

I urval från Stockholms universitets publikationsdatabas

  • Highly magnetic hybrid foams based on aligned tannic acid-coated iron oxide nanoparticles and TEMPO-oxidized cellulose nanofibers

    2023. Seyed Ehsan Hadi (et al.). RSC Advances 13 (20), 13919-13927

    Artikel

    Lightweight iron oxide nanoparticle (IONP)/TEMPO-oxidized cellulose nanofibril (TOCNF) hybrid foams with an anisotropic structure and a high IONP content were produced using magnetic field-enhanced unidirectional ice-templating. Coating the IONP with tannic acid (TA) improved the processability, the mechanical performance, and the thermal stability of the hybrid foams. Increasing the IONP content (and density) increased the Young's modulus and toughness probed in compression, and hybrid foams with the highest IONP content were relatively flexible and could recover 14% axial compression. Application of a magnetic field in the freezing direction resulted in the formation of IONP chains that decorated the foam walls and the foams displayed a higher magnetization saturation, remanence, and coercivity compared to the ice-templated hybrid foams. The hybrid foam with an IONP content of 87% displayed a saturation magnetization of 83.2 emu g−1, which is 95% of the value for bulk magnetite. Highly magnetic hybrid foams are of potential interest for environmental remediation, energy storage, and electromagnetic interference shielding.

    Läs mer om Highly magnetic hybrid foams based on aligned tannic acid-coated iron oxide nanoparticles and TEMPO-oxidized cellulose nanofibers
  • Thermally Insulating and Moisture-Resilient Foams Based on Upcycled Aramid Nanofibers and Nanocellulose

    2023. Andi Di (et al.). Advanced Materials

    Artikel

    Low-density foams and aerogels based on upcycled and bio-based nanofibers and additives are promising alternatives to fossil-based thermal insulation materials. Super-insulating foams are prepared from upcycled acid-treated aramid nanofibers (upANFA) obtained from Kevlar yarn and tempo-oxidized cellulose nanofibers (CNF) from wood. The ice-templated hybrid upANFA/CNF-based foams with an upANFA content of up to 40 wt% display high thermal stability and a very low thermal conductivity of 18–23 mW m−1 K−1 perpendicular to the aligned nanofibrils over a wide relative humidity (RH) range of 20% to 80%. The thermal conductivity of the hybrid upANFA/CNF foams is found to decrease with increasing upANFA content (5–20 wt%). The super-insulating properties of the CNF-upANFA hybrid foams are related to the low density of the foams and the strong interfacial phonon scattering between the very thin and partially branched upANFA and CNF in the hybrid foam walls. Defibrillated nanofibers from textiles are not limited to Kevlar, and this study can hopefully inspire efforts to upcycle textile waste into high-performance products.

    Läs mer om Thermally Insulating and Moisture-Resilient Foams Based on Upcycled Aramid Nanofibers and Nanocellulose
  • Unravelling the Hydration Barrier of Lignin Oleate Nanoparticles for Acid- and Base-Catalyzed Functionalization in Dispersion State

    2021. Adrian Moreno (et al.). Angewandte Chemie International Edition 60 (38), 20897-20905

    Artikel

    Lignin nanoparticles (LNPs) are promising renewable nanomaterials with applications ranging from biomedicine to water purification. However, the instability of LNPs under acidic and basic conditions severely limits their functionalization for improved performance. Here, we show that controlling the degree of esterification can significantly improve the stability of lignin oleate nanoparticles (OLNPs) in acidic and basic aqueous dispersions. The high stability of OLNPs is attributed to the alkyl chains accumulated in the shell of the particle, which delays protonation/deprotonation of carboxylic acid and phenolic hydroxyl groups. Owing to the enhanced stability, acid- and base-catalyzed functionalization of OLNPs at pH 2.0 and pH 12.0 via oxirane ring-opening reactions were successfully performed. We also demonstrated these new functionalized particles as efficient pH-switchable dye adsorbents and anticorrosive particulate coatings.

    Läs mer om Unravelling the Hydration Barrier of Lignin Oleate Nanoparticles for Acid- and Base-Catalyzed Functionalization in Dispersion State
  • A Stiff, Tough, and Thermally Insulating Air- and Ice-Templated Plant-Based Foam

    2022. Tamara L. Church (et al.). Biomacromolecules 23 (6), 2595-2602

    Artikel

    By forming and directionally freezing an aqueous foam containing cellulose nanofibrils, methylcellulose, and tannic acid, we produced a stiff and tough anisotropic solid foam with low radial thermal conductivity. Along the ice-templating direction, the foam was as stiff as nanocellulose–clay composites, despite being primarily methylcellulose by mass. The foam was also stiff perpendicular to the direction of ice growth, while maintaining λr < 25 mW m–1 K–1 for a relative humidity (RH) up to 65% and <30 mW m–1 K–1 at 80% RH. This work introduces the tandem use of two practical techniques, foam formation and directional freezing, to generate a low-density anisotropic material, and this strategy could be applied to other aqueous systems where foam formation is possible. 

    Läs mer om A Stiff, Tough, and Thermally Insulating Air- and Ice-Templated Plant-Based Foam
  • Assembly of cellulose nanocrystals and clay nanoplatelets studied by time-resolved X-ray scattering

    2021. Pierre Munier (et al.). Soft Matter 17 (23), 5747-5755

    Artikel

    Time-resolved small-angle X-ray scattering (SAXS) was used to probe the assembly of cellulose nanocrystals (CNC) and montmorillonite (MNT) over a wide concentration range in aqueous levitating droplets. Analysis of the SAXS curves of the one-component and mixed dispersions shows that co-assembly of rod-like CNC and MNT nanoplatelets is dominated by the interactions between the dispersed CNC particles and that MNT promotes gelation and assembly of CNC, which occurred at lower total volume fractions in the CNC:MNT than in the CNC-only dispersions. The CNC dispersions displayed a d proportional to phi(-1/2) scaling and a low-q power-law exponent of 2.0-2.2 for volume fractions up to 35%, which indicates that liquid crystal assembly co-exists and competes with gelation.

    Läs mer om Assembly of cellulose nanocrystals and clay nanoplatelets studied by time-resolved X-ray scattering
  • Colloidal Processing and Alignment of Wood-Based Dispersions and Hybrid Functional Foams

    2024. Seyed Ehsan Hadi.

    Avhandling (Dok)

    This thesis presents novel methods and approaches for designing, preparing/fabricating, and characterizing wood-based nanomaterials. It investigates how modifications in structure, process variables, and composition can enhance functional properties. It employs advanced characterization techniques to analyze process-structure-property relationships and utilizes innovative colloidal processing approaches such as controlled nanoparticle incorporation, Layer-by-Layer self-assembly, and unidirectional ice-templating to improve the functional properties of wood-based nanomaterials.

    A novel approach has been developed to fabricate lightweight, highly porous hybrid foams using iron oxide nanoparticles (IONP) and TEMPO-oxidized cellulose nanofibers (TOCNF). The addition of tannic acid (TA) and the application of a magnetic field-enhanced unidirectional ice-templating technique (MFUIT) enhanced processability, mechanical, and magnetic characteristics of the foams. The hybrid foam containing 87% IONPs exhibited a saturation magnetization of 83.2 emu g–1, which is equivalent to 95% of the magnetization value observed in bulk magnetite.

    Hybrid, anisotropic foams have been prepared by incorporation of reduced graphene oxide (rGO) onto the macropore-walls of anisotropic TOCNF foams using a liquid-phase Layer-by-Layer self-assembly method. These hierarchical rGO-TOCNF foams exhibit lower radial thermal conductivity (λr) across a wide range of relative humidity compared to control TOCNF foams.

    The shear-induced orientations and relaxations of multi-component dispersions containing cellulose nanocrystals (CNC) and montmorillonite nanoplatelets (MNT) have been studied by rheological small-angle X-ray scattering (Rheo-SAXS). The addition of MNT resulted in gelation and changes in flow behavior, shear responses, and relaxation dynamics. Rheo-SAXS measurements showed that CNC and MNT aligned under shear, creating aligned structures that relaxed upon shear removal. Gaining insights into shear-induced orientations and relaxation dynamics can aid in the development of advanced wood-based nanocomposite materials.

    Transmission Electron Microscopy (TEM) was employed to characterize lignin oleate nanoparticles (OLNPs) derived from abundant lignin waste. TEM analysis revealed that the OLNPs had a spherical shape and a core-shell structure. Upon drying, the particles tended to agglomerate due to the loss of electrostatic repulsion forces. This agglomeration behavior indirectly supports the hypothesis that oleate chains act as a hydration barrier, preventing water permeation into the particles. 

    Finally, a comprehensive study showed that TEMPO-oxidized lignocellulose nanofibers (TOLCNF)-based foams made from unbleached pulp can be used to prepare anisotropic, light-weight ice-templated foams with high mechanical strength. TOLCNF foams utilize lignin and hemicellulose to enhance properties while require less energy for production compared to TOCNF-based foams. This study emphasizes the potential for developing sustainable wood-based nanomaterials using TOLCNF.

    The results presented in this thesis offer valuable insights for further advancements of wood-based nanomaterials. 

    Läs mer om Colloidal Processing and Alignment of Wood-Based Dispersions and Hybrid Functional Foams

Visa alla publikationer av Ehsan Hadi vid Stockholms universitet