Nonconductive ferrofluids from permanently magnetic nanoplatelets hybridized with polar phosphonic ligands

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F25%3A00619854" target="_blank" >RIV/61388963:_____/25:00619854 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/25:00619854

Výsledek na webu

<a href="https://hdl.handle.net/11104/0368943" target="_blank" >https://hdl.handle.net/11104/0368943</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/d5dt00281h" target="_blank" >10.1039/d5dt00281h</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Nonconductive ferrofluids from permanently magnetic nanoplatelets hybridized with polar phosphonic ligands

Popis výsledku v původním jazyce

Ferrofluids composed of permanently magnetic nanoplatelets of barium hexaferrite (BHF NPLs) represent a remarkable class of materials that can form a ferromagnetic liquid state at sufficiently high concentrations. To date, the surfactant dodecylbenzenesulfonic acid (DBSA) has demonstrated an excellent colloidal stability of the BHF NPLs in alcohols. However, a key limitation of DBSA is its labile adsorption onto the NPLs, meaning that the surface coverage by surfactant molecules is highly sensitive to various factors. In this study, we demonstrate that polar ligands based on phosphonic acids and phosphonate esters offer a viable alternative to DBSA, providing enhanced robustness and colloidal stability in low-polar solvents. Phosphonic ligands with the different electron-withdrawing groups and alkyl chain lengths of the terminal chain and linker were synthesized. Their attachment to the surface of the BHF NPLs was studied for various conditions and followed by a combination of spectroscopic techniques, thermogravimetry, and electrokinetic measurements. The results confirmed the theoretically predicted surface condensation of the ligands onto the BHF NPLs surfaces at 120 °C in 1-hexanol, whereas at lower temperatures or in more polar solvents the ligands were mostly physisorbed. The NPL hybrids with chemisorbed ligands having surface densities of at least 0.4 molecules per nm2 formed stable ferrofluids in 1-hexanol. Due to the relatively low polarity of 1-hexanol, the ligands remain protonated and the ferrofluids have negligible electric conductivity and are suitable for the development of novel magneto-optic sensors that can operate under an electric field.

Název v anglickém jazyce

Nonconductive ferrofluids from permanently magnetic nanoplatelets hybridized with polar phosphonic ligands

Popis výsledku anglicky

Ferrofluids composed of permanently magnetic nanoplatelets of barium hexaferrite (BHF NPLs) represent a remarkable class of materials that can form a ferromagnetic liquid state at sufficiently high concentrations. To date, the surfactant dodecylbenzenesulfonic acid (DBSA) has demonstrated an excellent colloidal stability of the BHF NPLs in alcohols. However, a key limitation of DBSA is its labile adsorption onto the NPLs, meaning that the surface coverage by surfactant molecules is highly sensitive to various factors. In this study, we demonstrate that polar ligands based on phosphonic acids and phosphonate esters offer a viable alternative to DBSA, providing enhanced robustness and colloidal stability in low-polar solvents. Phosphonic ligands with the different electron-withdrawing groups and alkyl chain lengths of the terminal chain and linker were synthesized. Their attachment to the surface of the BHF NPLs was studied for various conditions and followed by a combination of spectroscopic techniques, thermogravimetry, and electrokinetic measurements. The results confirmed the theoretically predicted surface condensation of the ligands onto the BHF NPLs surfaces at 120 °C in 1-hexanol, whereas at lower temperatures or in more polar solvents the ligands were mostly physisorbed. The NPL hybrids with chemisorbed ligands having surface densities of at least 0.4 molecules per nm2 formed stable ferrofluids in 1-hexanol. Due to the relatively low polarity of 1-hexanol, the ligands remain protonated and the ferrofluids have negligible electric conductivity and are suitable for the development of novel magneto-optic sensors that can operate under an electric field.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10406 - Analytical chemistry

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Dalton Transactions

ISSN

1477-9226

e-ISSN

1477-9234

Svazek periodika

54

Číslo periodika v rámci svazku

19

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

17

Strana od-do

7906-7922

Kód UT WoS článku

001475089800001

EID výsledku v databázi Scopus

2-s2.0-105003577581