Modification of the Avrami treatment of crystallization to account for nucleus and interface

Cheng, Stephen Z. D.; Wunderlich, Bernhard

doi:10.1021/ma00189a031

Cited by 80 publications

(53 citation statements)

References 3 publications

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“…Although the n values were fractional, they were close to the expected integer value of 3.0 for this crystallization model as discussed by Avrami [6]. There are many reasons cited in the literature, such as non-uniform nucleation and non-negligible volume of nuclei for noninteger values of n [7].…”

Section: Isothermal Crystallization Rate Studysupporting

confidence: 79%

The kinetics of crystallization of poly(ε-caprolactone) measured by FTIR spectroscopy

Phillipson

Jenkins

Hay

2015

J Therm Anal Calorim

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The kinetics of crystallization of poly(ecaprolactone), PCL, have been measured by FTIR spectroscopy using the absorbance of the crystalline and amorphous phase carbonyl bands at 1725 and 1735 cm -1 , respectively, to determine the fractional crystallinity as a function of time and over the temperature range 43-47°C. A comparison was also made with DSC which was found to have limited sensitivity such that it could only measure the primary stage of the crystallization and not the secondary. Both primary and secondary crystallization could be measured by FTIR spectroscopy with sufficient accuracy to measure the kinetics of each and limited only by the length of time over which the measurements were made.

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Section: Isothermal Crystallization Rate Studysupporting

confidence: 79%

The kinetics of crystallization of poly(ε-caprolactone) measured by FTIR spectroscopy

Phillipson

Jenkins

Hay

2015

J Therm Anal Calorim

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“…The relatively low crystallinity of RR P3HT, which is about 15 %, as determined from heat of melting, [22] could be attributed to the soft impingement of alkyl side chains by the rigid amorphous portions hindering the crystalline-domain formation from RR P3HT chains. [23,24] In molten or solution state, the polymer main chain may adopt a coiled conformation; in order to crystallize into the crystalline lattice, it has to be straightened. However, the side chains may not favor the unfolding process readily, resulting in low crystallinity.…”

Section: Resultsmentioning

confidence: 99%

Effect of Mesoscale Crystalline Structure on the Field-Effect Mobility of Regioregular Poly(3-hexyl thiophene) in Thin-Film Transistors

et al. 2005

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Regioregular poly(3‐hexyl thiophene) (RR P3HT) is drop‐cast to fabricate field‐effect transistor (FET) devices from different solvents with different boiling points and solubilities for RR P3HT, such as methylene chloride, toluene, tetrahydrofuran, and chloroform. A Petri dish is used to cover the solution, and it takes less than 30 min for the solvents to evaporate at room temperature. The mesoscale crystalline morphology of RR P3HT thin films can be manipulated from well‐dispersed nanofibrils to well‐developed spherulites by changing solution processing conditions. The morphological correlation with the charge‐carrier mobility in RR P3HT thin‐film transistor (TFT) devices is investigated. The TFT devices show charge‐carrier mobilities in the range of 10–4 ∼ 10–2 cm2 V–1 s–1 depending on the solvent used, although grazing‐incidence X‐ray diffraction (GIXD) reveals that all films develop the same π–π‐stacking orientation, where the <100>‐axis is normal to the polymer films. By combining results from atomic force microscopy (AFM) and GIXD, it is found that the morphological connectivity of crystalline nanofibrils and the <100>‐axis orientation distribution of the π–π‐stacking plane with respect to the film normal play important roles on the charge‐carrier mobility of RR P3HT for TFT applications.

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“…Chang and Wunderlich (42,43) suggested that in similar situations, low values of n, even approaching zero, could be obtained. For example, crystallization from a viscous medium where mobility is restricted, described as a "cold crystallization," would restrict the rate of crystallite growth.…”

Section: Measurement Of Crystallization Kineticsmentioning

confidence: 94%

Investigation of mesophase transitions in liquid crystals using inverse gas chromatography

Price¹,

Shillcock²

1995

Can. J. Chem.

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Inverse Gas Chromatography, IGC, has been used to study phase transitions in three low molar mass liquid crystals and one side-chain liquid crystalline polymer. This extension of previous work has shown that transitions between all of the various mesophases can be detected and their temperatures measured with an accuracy and precision comparable to that of more conventional techniques. For one of the compounds, 4,4'-(n-hexyloxy)cyanobiphenyl, the kinetics of solidification from the supercooled nematic phase have been measured. The process took place in two stages which could be interpreted in terms of a modified version of the Avrami model of polymer crystallization. An explanation of the results is that the solid support is providing a large number of nucleation sites for the initial part of the solidification, which is completed in a slow, diffusionlimited process. However, further work is required to confirm this mechanism.Key words: inverse gas chromatography (IGC), liquid crystals, mesophase transitions, activity coefficients, retention volumes.Resume : On a utilisC la chromatographie en phase gazeuse inverse (IGC) pour Ctudier les transitions de phase de trois cristaux liquides de faibles masses molaires et d'un polymkre cristal-liquide avec chai'ne latCrale. Cette extension du travail prCcCdent a permis de dCmontrer que l'on peut dCtecter toutes les transitions entre les diverses mCsophases et de mesurer leurs tempkratures avec une exactitude et une prkcision comparables i celles des techniques plus conventionnelles. Pour l'un des composCs, le 4,4'-(n-hexyloxy)cyanobiphCnyle, on a mesurC la cinCtique de la solidification B partir de la phase nCmatique surrefroidie. Le processus se produit en deux Ctapes que l'on peut interpreter en fonction d'une version modifiCe du modkle d'Avrami de la cristallisation d'un polymkre. On peut expliquer les rksultats en supposant que le support solide fournit un grand nombre de sites de nuclCation pour la partie initiale de la solidification que est complCtCe par un processus lent, B diffusion limitCe. Toutefois, des travaux ultCrieurs seront nicessaires pour confirmer ce micanisme.

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Modification of the Avrami treatment of crystallization to account for nucleus and interface

Cited by 80 publications

References 3 publications

The kinetics of crystallization of poly(ε-caprolactone) measured by FTIR spectroscopy

The kinetics of crystallization of poly(ε-caprolactone) measured by FTIR spectroscopy

Effect of Mesoscale Crystalline Structure on the Field-Effect Mobility of Regioregular Poly(3-hexyl thiophene) in Thin-Film Transistors

Investigation of mesophase transitions in liquid crystals using inverse gas chromatography

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