Conformational transition studies of organosilane polymers by light and neutron scattering

Shukla, Premal; Cotts, Patricia M.; Miller, Robert D.; Russell, Thomas P.; Smith, Barton A.; Wallraff, G. M.; Baier, Mark; Thiyagarajan, P.

doi:10.1021/ma00020a020

Cited by 48 publications

(41 citation statements)

References 9 publications

(12 reference statements)

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“…The change in the quality of the solvent seems to induce a sort of intramolecular and/or intermolecular collapse of the macromolecules with distinctly different optical properties [12]. This general model is in agreement with light and neutron scattering measurements on polysilanes, which have revealed, at temperatures very near the thermochromic transition but prior to the onset of aggregation, a decrease in the radius of gyration of the polymers upon cooling [75]. Interestingly, changes in the applied pressure on polythiophene, polydiacetylene, or polysilane thin films can also induce so-called piezochromic effects [76][77][78].…”

Section: Solvatochromism and Piezochromismsupporting

confidence: 74%

Optical and Electrochemical Transducers Based on Functionalized Conjugated Polymers

Leclerc

2000

Sensors Update

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Section: Solvatochromism and Piezochromismsupporting

confidence: 74%

Optical and Electrochemical Transducers Based on Functionalized Conjugated Polymers

Leclerc

2000

Sensors Update

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“…The excluded Carbon Number Viscosity Index: volume parameter a is defined as a 2 hr 2 i=hr 2 i 0 , and has been reported to be less than 1.2 for DPB at 25 C in toluene, which is a better solvent than THF. 60 The low second virial coefficient of PD6 in THF (1:14 Â 10 À4 mL mol/g 2 ) also supports the small contributions of exclude volume effects on the conformations of polysilanes with longer segment lengths than PD6. 59,60 Thus, the assumption of a ¼ 1 gives an appropriate estimate of the segment length for DPB, PH5-PH12 and PD6-PD12, although the segment length of polysilanes with highly flexible backbones may be underestimated.…”

mentioning

confidence: 74%

“…60 The low second virial coefficient of PD6 in THF (1:14 Â 10 À4 mL mol/g 2 ) also supports the small contributions of exclude volume effects on the conformations of polysilanes with longer segment lengths than PD6. 59,60 Thus, the assumption of a ¼ 1 gives an appropriate estimate of the segment length for DPB, PH5-PH12 and PD6-PD12, although the segment length of polysilanes with highly flexible backbones may be underestimated. On the basis of the Si-Si bond length (0.2414 nm) and Si-Si-Si bond angle (114.…”

mentioning

confidence: 74%

Optoelectronic Properties and Nanostructure Formation of σ-Conjugated Polymers

Seki

Tagawa

2007

Polym J

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ABSTRACT:This paper reviews recent studies on the opto-electronic properties of -conjugated polymers as well as the nanostructure formation based on the polymeric materials by the single particle nanofabrication technique. The direct quantitative correlation has been found between backbone conformation of -conjugated polymers and delocalization of charge carriers along their conjugated backbones by transient spectroscopy of the ion radicals. The microwave conductivity measurement technique was applied to estimate the intra-chain mobility of the charge carriers, giving the value of isotropic mobility holes along the chains as ca.. This is suggestive that the potentials of rod-like conjugated backbones in polysilanes as 1-D semiconductor are competitive to those of amorphous silicon.Cross-linking reaction of the -conjugated polymers was firstly promoted by charged particle irradiation to the thin films in the present study. Non-homogeneous cross-linking reaction in the polymers gives clear nanowires whose sizes, length, and number density are fairly controlled by selecting particles, molecular weights, etc. We believe that the present technique is applicable to produce wire-like nanostructures based on a variety of polymeric materials via the simple cross-linking reaction schema.

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“…Early experiments with the helium-gas cell included studies of KN03-IV (Worlton et al, 1986), NDF4-II Gawson et al, 1989), Li (Smith et al, 1990), and Na (Smith et al, 1991). After the high-T, oxide superconductors were discovered and it was realized that pressure had rather dramatic effects on the superconducting properties, which could provide important insights into the underlying physics, a number of high-pressure neutron diffraction experiments were performed on these materials.…”

Section: Section "B-b"mentioning

confidence: 99%

Intense Pulsed Neutron Source: Progress report 1991--1996. 15. Anniversary edition -- Volume 2

1996

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Introduct i .on I n May 1981, the proton beam was first delivered to the Intense Pulsed Neutron Source (IPNS) target at Argonne National Laboratory and now, in May 1996, the 15th anniversary of this historic event is being celebrated. In addition, this special IPNS Progress Report, which contains a summary of developments and scientific accomplishments, is being disseminated.In the five years since the 10th anniversary, a great deal of activity took place at IPNS, and many improvements were made. More than 1,300 experiments were performed, and more than 900 scientists conducted at least one experiment during any given year. Many of the scientific results achieved at IPNS were significant, and they involved a broad range of disciplines.During this time, several new instruments were added:The glass, liquid, and amorphous materials diffractometer (GLAD) was added to the user program in 1992. The small-angle diffractometer (SAND) was commissioned in 1993. The chemical excitations spectrometer (CHEX) was constructed in record time during the summer of 1995. CHEX was put on the beamline formerly occupied by PHOENIX, which had been very successful in performing deep inelastic scattering for 10 years and, more recently, in performing diffraction experiments in quantum systems.Fiscal year (FY) 1996 has been especially exciting because the IPNS operating budget has increased by 50% as part of the Scientific Facilities Initiative. This funding will enable IPNS to double its operating time and provide the scientific and technical support necessary to allow all instruments involved in the user program to be operated at their full capacity.Argonne also made a major contribution to the development of pulsed sources in the last five years, conceiving, developing, and documenting a feasibility study for a new, world-class pulsed spallation source. This "IPNS Upgrade" was originally designed to be a 1-MW source with two target stations and 36 beamlines, having six times the beam power of ISIS (the most powerful source operating in the world) and saving $175 million by using existing buildings and infrastructure. The feasibility study was reviewed in April 1995. In response to guidance from the U S . Department of Energy (DOE), the design was scaled down to a 400-kW source with 18 beamlines and 2.5 times the power of ISIS. This plan is now under review by DOE'S Basic Energy Sciences Advisory Committee. In addition, an effort has begun to design and prepare a detailed cost estimate of an ISIS-level source (150 KW), which would again realize large savings by using existing buildings.Already, the scientific capabilities of the four short pulsed spallation sources that operate worldwide have been shown to be significant. It is therefore vital that the United States have I N T R O D U C T I O NIntense Pulsed Neutron Source control room. William Sullivan is updating the accelerator log book, and James Spindler is at the accelerator controls. years" is left to the reader. Suffice it to say that, like a fine wine, the IPNS accelerator ha...

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Conformational transition studies of organosilane polymers by light and neutron scattering

Cited by 48 publications

References 9 publications

Optical and Electrochemical Transducers Based on Functionalized Conjugated Polymers

Optical and Electrochemical Transducers Based on Functionalized Conjugated Polymers

Optoelectronic Properties and Nanostructure Formation of σ-Conjugated Polymers

Intense Pulsed Neutron Source: Progress report 1991--1996. 15. Anniversary edition -- Volume 2

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