Surface tension of cavities and Tolman’s length in n-alkanes. A positron study

Zgardzińska, B.; Goworek, T.

doi:10.1016/j.chemphys.2012.12.004

Cited by 9 publications

(7 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the simplest case, Ps is considered as a point particle that is assumed to be situated in a fi nite square well potential. If the fi nite square well potential is replaced by an infinitely deep square well potential, the radius of the well R + d is broadened by a parameter d [18,19]. Then, E Ps (R) =  2 ħ 2 /4m 0 (R + d) 2 , where m 0 is the mass of an electron.…”

Section: Positron Annihilation In Liquid Crystalsmentioning

confidence: 99%

Positron annihilation in liquid crystals

Dryzek

Juszyńska-Gałązka

2015

Nukleonika

View full text Add to dashboard Cite

Abstract. Positron annihilation studies of liquid crystals are reviewed with particular reference to thermotropic liquid crystals with rod-like molecules. The studies of compounds exhibiting smectic A or smectic E phases indicate that local arrangement of dipole molecules play an important role because high electron density at the end group of molecules can infl uence substantially formation and annihilation of positronium. The obtained ortho-positronium lifetimes in these phases can be explained by antiparallel pairing of molecules in case of the smectic A phase or a structure with a nanosegregation of alkyl chains and others parts of molecules into sublayers and liquid-like state of alkyl chains in case of the smectic E phase.

show abstract

Section: Positron Annihilation In Liquid Crystalsmentioning

confidence: 99%

Positron annihilation in liquid crystals

Dryzek

Juszyńska-Gałązka

2015

Nukleonika

View full text Add to dashboard Cite

show abstract

“…With the rise of temperature that lifetime rises too, the dependence of τ 3 on the temperature above the melting point is very similar for all alkanes under study, from heptane C7 to hexatriacontane C36 (Fig.50), with a slight tendency to decrease the slope dτ 3 /dT with increasing molecular length [137]. The rise of τ 3 with temperature reflects the common property of liquids -decrease of surface tension.…”

Section: Molten Alkanes and Alcoholsmentioning

confidence: 69%

“…If we assume, following the existing literature data, U = 1.0 eV and the radii according to the Tao-Eldrup model, then for alkanes near the melting point we obtain the Tolman's length 0.05 to 0.06 nm, i.e. of the order of atomic radius [137]. The surface tension of the Ps bubbles is increased 1.4 to 1.5 times compared to a flat surface.…”

Section: The Bubble Modelmentioning

confidence: 83%

“…In liquid primary alcohols (1-alkanols) the o-Ps lifetime dependence on temperature above the melting point is similar to that in alkanes: monotonous I 3 rise, weakly dependent on the length n of carbon chain. Along the homologous series the change of I 3 intensity with temperature shows some peculiarities: in the shortest chain alcohols I 3 is almost independent on temperature, but then dI 3 /dT increases systematically with rising chain length n. Usually the o-Ps intensity in solid phase is larger than in liquid one, but that step diminishes with n up to the change of its sign at n = 16 [137]. …”

Section: Molten Alkanes and Alcoholsmentioning

confidence: 97%

See 1 more Smart Citation

Positronium as a probe of small free volumes in crystals, polymers and porous media

Goworek¹

2014

Annales UMCS, Chemia

Self Cite

View full text Add to dashboard Cite

show abstract

“…The use of a positronium probe gives us an opportunity to investigate the effect of pressure on the nanoscale structure of aerogels. Our earlier studies of PALS parameters as a function of pressure performed on the large group of organic compounds and of the phase change materials (PCM microcapsules) show that structural changes in the nano-size scale significantly depend on the form of pressure exerted [1][2][3][4][5][6][7][8][9]. In each case, the greater destructive effect was observed when pressure was exerted mechanically.…”

Section: Introductionmentioning

confidence: 96%

Aerogel IC3120 Under High Pressure Exerted Mechanically and by Nitrogen

Gorgol

Zgardzińska

2017

Acta Phys. Pol. A

View full text Add to dashboard Cite

Highly porous IC3120 silica aerogel was subjected to the high pressure up to 450 MPa while the positron annihilation lifetime spectra were collected. The pressure was delivered to the investigated samples in two ways: by pistons and by gas (nitrogen) penetrating the aerogel. The evolution of all PALS parameters was discussed. With the increase of the pressure, shortening of ortho-positronium lifetimes (different, depending on the pressure method introduced) was observed. Similarity between the dependence of the longest-lived o-Ps component lifetime on the pressure, for the sample affected with nitrogen molecules and pure nitrogen was observed. It suggests, that the nitrogen fills the largest free volumes of the aerogel. The pressure exerted mechanically causes much smaller decrease of free volume available for positronium. The comparison of PALS results with the electron microscopy images, obtained after removing the pressure, confirmed that more intense and lasting changes were caused by affecting the aerogel with the pistons.

show abstract

Surface tension of cavities and Tolman’s length in n-alkanes. A positron study

Cited by 9 publications

References 25 publications

Positron annihilation in liquid crystals

Positron annihilation in liquid crystals

Positronium as a probe of small free volumes in crystals, polymers and porous media

Aerogel IC3120 Under High Pressure Exerted Mechanically and by Nitrogen

Contact Info

Product

Resources

About