Impact of Confinement on the Dynamics and H-Bonding Pattern in Low-Molecular Weight Poly(propylene glycols)

Talik, Agnieszka; Tarnacka, Magdalena; Geppert‐Rybczyńska, Monika; Hachuła, Barbara; Kamiński, Kamil; Paluch, Marian

doi:10.1021/acs.jpcc.0c04062

Cited by 10 publications

(17 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For all those materials, we can observe two endothermic signals discussed in the literature as a so-called double glass transition (DGT) phenomenon where both T g values are located above and below the one observed for the bulk material independent of the molecular weight of PhAs and pore diameters (see Figure b,c and Figure f,g). One can recall that similar findings are commonly reported in the literature for various glass formers under confinement, ,,− including materials able to create excessive hydrogen bonding structures. According to the “two-layer” (or “core-shell”) model, , there are different types of interactions within infiltrated materials, which result in heterogeneity in terms of molecular dynamics as well as packing density .…”

Section: Resultssupporting

confidence: 83%

Impact of Nanostructurization of the Pore Walls on the Dynamics of a Series of Phenyl Alcohols Incorporated within Nanoporous Aluminum Oxide Templates

et al. 2022

Self Cite

View full text Add to dashboard Cite

Herein, we studied the impact of surface roughness on the molecular dynamics of a series of phenyl-terminated monohydroxyalcohols under spatial confinement provided by nanoporous anodic aluminum oxide (AAO) membranes of constant (const-AAO) and modulated (modul-AAO) pore diameter using Broadband Dielectric Spectroscopy and Differential Scanning Calorimetry. Interestingly, we observed that both types of AAO membranes affect the behavior of examined associating materials in a different manner. Calorimetric measurements showed that the double glass transition phenomenon, commonly reported for many compounds infiltrated into const-AAO membranes, is not observed in the case of modul-AAO templates, where a single glass transition temperature was detected. Consequently, the dynamics of the dominant process was bulk-like in the whole range of studied temperatures for the samples infiltrated into the latter templates. Moreover, the Debye character of the dominant relaxation process characteristic for bulk samples was lost for the confined samples. Interestingly, the width of the dominant mode was the greatest in the alcohols infiltrated into modulated pores. It was assigned to the higher heterogeneity in the mobility introduced by the nanostructurization of the interface. The presented data emphasize the crucial impact of modulated-induced surface roughness of an applied constrained medium on the dynamics and phase transition of the liquids infiltrated into pores.

show abstract

Section: Resultssupporting

confidence: 83%

Impact of Nanostructurization of the Pore Walls on the Dynamics of a Series of Phenyl Alcohols Incorporated within Nanoporous Aluminum Oxide Templates

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…This finding indicates the occurring of an additional third glass transition temperature of unknown origin (labeled as T g,add ). In this context, one can recall some earlier works on poly(methyl methacrylate) (PMMA), 72 PPG, 63 and PMPS 71 confined within AAO porous templates, reporting the existence of the third T g , located between T g,core and T g,interfacial upon different heating/cooling rates due to the formation of the intermediate layer between the adsorbed and core molecules. 72 However, in our case, the additional T g, add is located far above T g,interfacial , suggesting a different origin of this anomalous glass transition temperature.…”

Section: Resultsmentioning

confidence: 91%

“…Since recent studies on various low- and high- molecular weight glass formers infiltrated into AAO templates have indicated that the structural/segmental dynamics strongly depends on the thermal history of the confined sample, − we decided to explore this effect on spatially restricted PROa compound that is characterized by one of the highest pressure coefficient of the glass transition temperature, d T g /d p = 427 K/GPa. For that purpose, dielectric measurements on the confined API were performed using two different temperature protocols described in detail in the Experimental Section.…”

Section: Resultsmentioning

confidence: 99%

Anormal Thermal History Effect on the Structural Dynamics of Probucol Infiltrated into Porous Alumina

et al. 2021

Self Cite

View full text Add to dashboard Cite

Herein, broadband dielectric (BDS) and Fourier transform infrared spectroscopy (FTIR), together with differential scanning calorimetry (DSC) and X-ray diffraction (XRD), were applied to study the molecular dynamics, molecular interactions as well as physical stability of an amorphous Active Pharmaceutical Ingredient (API) probucol (PRO)infiltrated into anodic aluminum oxide (AAO) membranes of pore size, d ∼ 10−160 nm. Interestingly, the behavior of examined substance strongly depends on the applied thermal protocol. Remarkably, for the first time, we observed that the structural dynamics of the slowly cooled PRO under confinement is significantly enhanced when compared to that of the quenched material. This unusual behavior was interpreted as a result of surface-induced effects (including the formation of well-resolved interfacial H-bonded layer and adsorption− desorption processes near the interface) that are magnified by the extremely high sensitivity to density fluctuation of studied PRO, reflected in the enormous pressure coefficient of the glass transition temperature dT g /dp = 427 K/GPa. In fact, FTIR investigations revealed that PRO tends to self-associate under confinement and forms a strongly bonded interfacial layer, which controls the variation in the structural dynamics of core molecules. Finally, we observed that the tendency to crystallize of confined API is reduced with respect to the bulk, even though the critical size of PRO nuclei (r c ∼ 3 nm) is significantly lower than the smallest examined pore size. Nevertheless, after few weeks of storage, the investigated substance crystallized in larger pores, while it remained stable in the nanochannels of d = 10 nm. A combination of XRD and DSC measurements indicated that the infiltrated PRO forms two polymorphs, the stable form I (dominating in bulk) and unstable form II (prevailing under confinement). That means that porous matrices might be used to obtain and maintain prolonged stability of unstable polymorphic forms of API.

show abstract

“…Therefore, in this paper, we focused exclusively on the analysis of the α-process. It is also worth adding that in the case of incorporated CLN, there was no sign of the “interfacial process” related to the reorientational motions of the molecules adsorbed at the surface of the pore walls, reported in the literature for various glass formers infiltrated into porous membranes (especially silica ones). − Herein, it should be stressed that the presence or absence of this mode depends on many factors, for example, the time scale of the mass exchange between interfacial and core molecules, and the experiment time . The lack of the interfacial process in the loss spectra of the examined compound can be related to the fact that the exchange between both fractions of molecules is slow with respect to the time of the experiment. , …”

Section: Introductionmentioning

confidence: 95%

Studying the Intermolecular Interactions, Structural Dynamics, and Non-Equilibrium Kinetics of Cilnidipine Infiltrated into Alumina and Silica Pores

et al. 2022

Self Cite

View full text Add to dashboard Cite

In the present study, the behavior of the calcium channel blocker cilnidipine (CLN) infiltrated into silica (SiO 2 ) and anodic aluminum oxide (AAO) porous membranes characterized by a similar pore size (d = 8 nm and d = 10 nm, respectively) as well as the bulk sample has been investigated using differential scanning calorimetry, broadband dielectric spectroscopy (BDS), and Fourier-transform infrared spectroscopy (FTIR) techniques. The obtained data suggested the existence of two sets of CLN molecules in both confined systems (core and interfacial). They also revealed the lack of substantial differences in inter-and intramolecular dynamics of nanospatially restricted samples independently of the applied porous membranes. Moreover, the annealing experiments (isothermal time-dependent measurements) performed on the confined CLN clearly indicated that the whole equilibration process under confinement is governed by structural relaxation. It was also found that the β anneal parameters obtained from BDS and FTIR data upon equilibration of both confined samples are comparable (within 10%) to each other, while the equilibration constants are significantly different. This finding strongly emphasizes that there is a close connection between the inter-and intramolecular dynamics under nanospatial restriction.

show abstract

Impact of Confinement on the Dynamics and H-Bonding Pattern in Low-Molecular Weight Poly(propylene glycols)

Cited by 10 publications

References 72 publications

Impact of Nanostructurization of the Pore Walls on the Dynamics of a Series of Phenyl Alcohols Incorporated within Nanoporous Aluminum Oxide Templates

Impact of Nanostructurization of the Pore Walls on the Dynamics of a Series of Phenyl Alcohols Incorporated within Nanoporous Aluminum Oxide Templates

Anormal Thermal History Effect on the Structural Dynamics of Probucol Infiltrated into Porous Alumina

Studying the Intermolecular Interactions, Structural Dynamics, and Non-Equilibrium Kinetics of Cilnidipine Infiltrated into Alumina and Silica Pores

Contact Info

Product

Resources

About