Analysis of transitions of liquid crystals and conformationally disordered crystals by temperature-modulated calorimetry

Chen, Wei; Toda, Akihiko; Moon, I.; Wunderlich, Bernhard

doi:10.1002/(sici)1099-0488(19990701)37:13<1539::aid-polb20>3.0.co;2-t

Cited by 18 publications

(11 citation statements)

References 24 publications

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“…However, the “undercooling” (criterion 8) as defined by the difference between the melting/isotropization and crystallization/ordering temperatures and the entropy of fusion/isotropization (criterion 3) are particularly useful parameters for distinguishing between these three possibilities. Liquid crystals undergo near‐equilibrium transitions and do not need to undergo nucleation, unlike condis or fully ordered crystals. Figure (a–c) show DSC scans for heating and cooling for P3HT, pBTTT‐C 14 , and pATBT‐C 14 , respectively.…”

Section: Resultsmentioning

confidence: 99%

“…For polymeric materials the primary phase characterizations are typically limited to amorphous glasses, positionally disordered glasses (liquid crystal glass), conformationally disordered glasses (condis glass), liquid crystals, condis crystals, “normal” crystals, and isotropic melts. As pointed out by Wunderlich, based on some similarities in morphological structures and X‐ray diffraction‐based structural considerations alone, the LC and condis mesophases have been incorrectly considered the same. The thermodynamic and kinetic behaviors are distinct as shown in Table , criteria 3, 4 and 8, and are therefore, particularly discernible by calorimetry.…”

Section: Introductionmentioning

confidence: 99%

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Classification of semiconducting polymeric mesophases to optimize device postprocessing

Snyder

Kline

DeLongchamp

et al. 2015

J Polym Sci B Polym Phys

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Semiconducting polymers form a variety of phases and mesophases that respond differently to postdeposition solvent or thermal treatments. Here it is shown that classification of these materials into their appropriate mesophases can be a useful tool to optimize their thermal postdeposition treatments. Calorimetry is used to quantify differences between materials having similar molecular structures, using a well‐established framework based on the kinetics and thermodynamics of phase changes. By way of example, this classification scheme is used to identify differences in three polymers, poly(3‐hexylthiophene‐2,5‐diyl) and two isomeric bithiophene–thienothiophene copolymers. It is demonstrated that poly(3‐hexylthiophene) is a “normal” polymer crystal and that the two bithiophene–thienothiophene copolymers have liquid crystalline phases. The different phase structure is notable in light of the molecular similarity of the three polymers and has an impact on the thermal postprocessing conditions that maximize field effect charge carrier mobility in thin film transistor devices. Strong superheating effects are demonstrated for the two bithiophene–thienothiophene copolymers and the impact on annealing is demonstrated using grazing incidence X‐ray diffraction. Some suggestions are also put forth for what post‐processing should be employed for each class of polymer. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 1641–1653

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Classification of semiconducting polymeric mesophases to optimize device postprocessing

Snyder

Kline

DeLongchamp

et al. 2015

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

show abstract

“…Reversible melting and crystallization could be demonstrated with quasi-isothermal TMDSC for small molecules (paraffins, 38 nucleated indium 39 ) and also for liquid crystals 40 of small and large molecules. One must, thus, look for local structures similar to such materials to account for reversible melting and crystallization in polymers, consisting of short chain segments and/or parallel oriented portions of the chain.…”

Section: Discussionmentioning

confidence: 99%

Reversible and irreversible heat capacity of poly(trimethylene terephthalate) analyzed by temperature-modulated differential scanning calorimetry

Pyda

Wunderlich

2000

J. Polym. Sci. B Polym. Phys.

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“…The existence of liquid crystalline states can be verified by DSC; additional peaks other than melting or crystallization peaks during heating or cooling indicate the existence of mesophases. However, further efforts are needed to distinguish liquid crystalline states with conformationally disordered crystals . For conjugated polymers with rigid backbones, thermal analysis usually cannot provide clear information on the liquid crystallinity.…”

Section: Liquid Crystallinity State Assisted Morphology Controlmentioning

confidence: 99%

Liquid Crystal Ordering on Conjugated Polymers Film Morphology for High Performance

Zhang

Zhao

et al. 2019

J Polym Sci B Polym Phys

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The electronic performance of conjugated polymers depends on the microstructure of the polymer films. A percolated network morphology with high crystallinity, ordered intermolecular packing and long‐range order is beneficial for charge transport. In recent reports, some conjugated polymers have been shown to exhibit liquid crystallinity. The appearance of liquid crystalline ordering provides a new solution to solve the difficulties in microstructure manipulation. In this review, we summarize how liquid crystallinity can assist molecular arrangement and guide long‐range orientation during film processing, leading to high charge mobility. We expect that this article could draw more attention to the liquid crystallinity of conjugated polymers. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1572–1591

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Analysis of transitions of liquid crystals and conformationally disordered crystals by temperature-modulated calorimetry

Cited by 18 publications

References 24 publications

Classification of semiconducting polymeric mesophases to optimize device postprocessing

Classification of semiconducting polymeric mesophases to optimize device postprocessing

Reversible and irreversible heat capacity of poly(trimethylene terephthalate) analyzed by temperature-modulated differential scanning calorimetry

Liquid Crystal Ordering on Conjugated Polymers Film Morphology for High Performance

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