Molecular Weight Induced Conformational Change and Its Impact on β-Phase Formation of Polydiarylfluorene in Dilute Solution

2020 ◽  
Vol 124 (11) ◽  
pp. 6304-6310 ◽  
Author(s):  
Masaru Nagai ◽  
Jie Liu ◽  
Wei Huang ◽  
Moriya Kikuchi ◽  
Seigou Kawaguchi ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Conformational Change ◽  
Phase Formation ◽  
Dilute Solution ◽  
Β Phase

Molecular weight dependency of β phase formation in injection‐molded isotactic polypropylene

2019 ◽  
Vol 137 (15) ◽  
pp. 48555 ◽  
Author(s):  
Xiao Yang ◽  
Cristina Tuinea‐Bobe ◽  
Ben Whiteside ◽  
Phil Coates ◽  
Ying Lu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Phase Formation ◽  
Isotactic Polypropylene ◽  
Β Phase ◽  
Injection Molded

scholarly journals Kinetics and Thermodynamics of Poly(9,9-dioctylfluorene)β-Phase Formation in Dilute Solution

2006 ◽  
Vol 39 (17) ◽  
pp. 5854-5864 ◽  
Author(s):  
Fernando B. Dias ◽  
Jorge Morgado ◽  
António L. Maçanita ◽  
Fernando P. da Costa ◽  
Hugh D. Burrows ◽  
...  
Keyword(s):  
Phase Formation ◽  
Dilute Solution ◽  
Kinetics And Thermodynamics ◽  
Β Phase

scholarly journals Comparative Study of PVDF Sheets and Their Sensitivity to Mechanical Vibrations: The Role of Dimensions, Molecular Weight, Stretching and Poling

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1637
Author(s):  
Miroslav Mrlík ◽  
Josef Osička ◽  
Martin Cvek ◽  
Markéta Ilčíková ◽  
Peter Srnec ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Comparative Study ◽  
Vinylidene Fluoride ◽  
Initial Thickness ◽  
Complementary Method ◽  
Β Phase ◽  
Vibration Sensing ◽  
Poly Vinylidene Fluoride ◽  
Processing Techniques ◽  
The Comparative Study

This paper is focused on the comparative study of the vibration sensing capabilities of poly(vinylidene fluoride) (PVDF) sheets. The main parameters such as molecular weight, initial sample thickness, stretching and poling were systematically applied, and their impact on sensing behavior was examined. The mechanical properties of prepared sheets were investigated via tensile testing on the samples with various initial thicknesses. The transformation of the α-phase to the electro-active β-phase was analyzed using FTIR after applying stretching and poling procedures as crucial post-processing techniques. As a complementary method, the XRD was applied, and it confirmed the crystallinity data resulting from the FTIR analysis. The highest degree of phase transformation was found in the PVDF sheet with a moderate molecular weight (Mw of 275 kDa) after being subjected to the highest axial elongation (500%); in this case, the β-phase content reached approximately 90%. Finally, the vibration sensing capability was systematically determined, and all the mentioned processing/molecular parameters were taken into consideration. The whole range of the elongations (from 50 to 500%) applied on the PVDF sheets with an Mw of 180 and 275 kDa and an initial thickness of 0.5 mm appeared to be sufficient for vibration sensing purposes, showing a d33 piezoelectric charge coefficient from 7 pC N−1 to 9.9 pC N−1. In terms of the d33, the PVDF sheets were suitable regardless of their Mw only after applying the elongation of 500%. Among all the investigated samples, those with an initial thickness of 1.0 mm did not seem to be suitable for vibration sensing purposes.

Control of β-phase formation in polyfluorene thin films via Franck–Condon analysis

2003 ◽  
Vol 139 (3) ◽  
pp. 905-907 ◽  
Author(s):  
Amena L.T. Khan ◽  
Michael J. Banach ◽  
Anna Köhler
Keyword(s):  
Thin Films ◽  
Phase Formation ◽  
Β Phase ◽  
Franck Condon
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