Confined effects on structural isomers in the MCM-41-SIL matrix as seen by extrinsic probes via PALS and ESR: n-butanol vs tert-butanol

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F21%3A00544637" target="_blank" >RIV/61389013:_____/21:00544637 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.acs.org/doi/10.1021/acs.jpcc.1c01951" target="_blank" >https://pubs.acs.org/doi/10.1021/acs.jpcc.1c01951</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.jpcc.1c01951" target="_blank" >10.1021/acs.jpcc.1c01951</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Confined effects on structural isomers in the MCM-41-SIL matrix as seen by extrinsic probes via PALS and ESR: n-butanol vs tert-butanol

Popis výsledku v původním jazyce

The structural–dynamic states of n-butanol (n-BuOH) and tert-butanol (t-BuOH) isomers as representatives of a linear or globular protic polar medium in the bulk and confined states in the Mobile Composition Matter-41 (MCM-41) matrix obtained from the free volume and phase behavior using positron annihilation lifetime spectroscopy (PALS) or differential scanning calorimetry (DSC), respectively, together with the spectral properties and related mobility and interaction of the spin probe (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) using electron spin resonance (ESR), are presented. In the bulk t-BuOH, the typical τ3 vs T response for strongly crystallizing globular organics with a stepwise effect in the vicinity of Tm is found. On the other hand, the bulk n-BuOH exhibits a complicated course depending on thermal cycling due to the distinct crystallization ability of the linear constituents due to their intermolecular H-bonding. Under confinement, both n-BuOH and t-BuOH media in the MCM-41-SIL matrix were amorphized and heterogenized with larger mean free volume sizes and strong broadening of their dispersion with respect to the corresponding bulk states. In addition, very distinct temperature dependences in τ3 vs T/Tg plots with some anomalous effect in the subplateau region in the linear isomer correlating with the DSC response are observed. In the ESR experiment, a drastic difference in the most pronounced characteristic ESR temperature marking a transition from the slow-to-fast-motion regime with the following relations was found: T50G(b) ≅ TmDSC(b) for n-BuOH against T50G(b) ≪ TmDSC(b) for t-BuOH, where TmDSC(b) is the respective melting point. Further, several changes in the TEMPO mobility in both BuOH media are related to the numerous dynamic and thermodynamic transitions as obtained from measured DSC, PALS, and literary viscosity data. Finally, the changes in hyperfine splitting constants of TEMPO sensitively reflect the altered structural–dynamic relationships in both confined BuOH isomers with close coincidences between all three characteristic PALS and ESR temperatures, indicating the same origin of the underlying processes behind the changes in spin probe mobility or free volume expansion.

Název v anglickém jazyce

Confined effects on structural isomers in the MCM-41-SIL matrix as seen by extrinsic probes via PALS and ESR: n-butanol vs tert-butanol

Popis výsledku anglicky

The structural–dynamic states of n-butanol (n-BuOH) and tert-butanol (t-BuOH) isomers as representatives of a linear or globular protic polar medium in the bulk and confined states in the Mobile Composition Matter-41 (MCM-41) matrix obtained from the free volume and phase behavior using positron annihilation lifetime spectroscopy (PALS) or differential scanning calorimetry (DSC), respectively, together with the spectral properties and related mobility and interaction of the spin probe (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) using electron spin resonance (ESR), are presented. In the bulk t-BuOH, the typical τ3 vs T response for strongly crystallizing globular organics with a stepwise effect in the vicinity of Tm is found. On the other hand, the bulk n-BuOH exhibits a complicated course depending on thermal cycling due to the distinct crystallization ability of the linear constituents due to their intermolecular H-bonding. Under confinement, both n-BuOH and t-BuOH media in the MCM-41-SIL matrix were amorphized and heterogenized with larger mean free volume sizes and strong broadening of their dispersion with respect to the corresponding bulk states. In addition, very distinct temperature dependences in τ3 vs T/Tg plots with some anomalous effect in the subplateau region in the linear isomer correlating with the DSC response are observed. In the ESR experiment, a drastic difference in the most pronounced characteristic ESR temperature marking a transition from the slow-to-fast-motion regime with the following relations was found: T50G(b) ≅ TmDSC(b) for n-BuOH against T50G(b) ≪ TmDSC(b) for t-BuOH, where TmDSC(b) is the respective melting point. Further, several changes in the TEMPO mobility in both BuOH media are related to the numerous dynamic and thermodynamic transitions as obtained from measured DSC, PALS, and literary viscosity data. Finally, the changes in hyperfine splitting constants of TEMPO sensitively reflect the altered structural–dynamic relationships in both confined BuOH isomers with close coincidences between all three characteristic PALS and ESR temperatures, indicating the same origin of the underlying processes behind the changes in spin probe mobility or free volume expansion.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2021

Kód důvěrnosti údajů

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

Název periodika

Journal of Physical Chemistry C

ISSN

1932-7447

e-ISSN

1932-7455

Svazek periodika

125

Číslo periodika v rámci svazku

29

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

16

Strana od-do

15796-15811

Kód UT WoS článku

000680445800004

EID výsledku v databázi Scopus

2-s2.0-85111597830