The Packing of polymer molecules

Slonimskii, G.L.; Аскадский, А.А.; Китайгородский, А. И.

doi:10.1016/0032-3950(70)90345-x

Cited by 174 publications

(92 citation statements)

References 8 publications

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“…Molar refraction [R] is taken as the sum of atomic refractions. Intrinsic molecular volume V int of monomer unit for amorphous polymer can be calculated from the atomic radius and bond length of the constituent atoms based on the method developed by Slonimskii et al 20 When an atom A (atomic radius R) is bound to atom A i (atomic radius R i ) with bond length d i , the atomic volume ∆V (A) of atom A is given by …”

Section: Resultsmentioning

confidence: 99%

Structural Relaxation and Refractive Index of Low-Loss Poly(methyl methacrylate) Glass

Tanio

2002

Polym J

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KEY WORDSStructural Relaxation / Physical Aging / Refractive Index / Prism Coupling / Light Scattering Loss / Glass Transition Temperature / Poly(methyl methacrylate) / Amorphous polymer glasses are essentially in thermodynamic non-equilibrium states. Physical aging 1 describes the time dependence of change in the behavior of a polymer glass held at temperatures below the glass transition. Such change is normally the result of continuous slow relaxation of the glass from its initial non-equilibrium state towards the final thermodynamic equilibrium state. Thermodynamical properties such as volume 2, 3 or enthalpy 4, 5 have been mainly considered for the study of this phenomenon. Many properties of amorphous polymer glasses are affected by aging. Recently, we investigated the effects of enthalpy relaxation on light scattering loss of low-loss Poly(methylmethacrylate) (PMMA) glass which had no excess scattering, and concluded that light scattering loss of glassy PMMA is not affected inherently by physical aging due to approach to thermodynamic equilibrium at a temperature below glass transition temperature (T g ). 6 In this paper, the volume relaxation of low-loss PMMA glass was studied by using optical prism coupling method. We measured the change of refractive indices of low-loss PMMA glass with annealing at temperatures below T g , and tried to determine the volume relaxation by physical aging. EXPERIMENTAL Preparation of PMMA GlassAfter ordinary purification of methyl methacrylate (MMA) monomer with a distillation (bp 46-47 • C/100 mmHg) and 0.2 µm membrane filter, rigorous purification was carried out as follows: Ampoule A with distilled monomer was connected with two ampoules B and C carefully purified. Here, di-tert-butyl peroxide (DBPO) as an initiator and n-butyl mercaptan (nBM) as a chain transfer agent were placed in ampoule B, and ampoule C was empty. Ampoules A and B were frozen with liquid nitrogen, evacuated, and substituted by nitrogen. The monomers, DBPO, and nBM were degassed by several freeze-thaw cycles, and slowly distilled into the ampoule C under vacuum by cooling ampoule C with liquid nitrogen. Ampoule C was sealed under vacuum and immersed in silicone oil for polymerization. After polymerization, the cylindrical polymer sample with a 20 mm diameter was removed from ampoule C for measurement. Enthalpy Relaxation MeasurementEnthalpy relaxation of polymer glasses was measured by DSC (Shimadzu Co., DSC-50). The following standard thermal history was employed for the low-loss PMMA sample: 1) To eliminate the effects of previous thermal history after polymerization, the PMMA sample was annealed at 110 • C for 3 h.2) The PMMA sample was annealed for an aging time of t a at chosen aging temperatures (T a ).3) The PMMA sample was quenched down to the room temperature. 4) DSC measurements were carried out with increasing temperature from room temperature to 170 • C at a heating rate of 10 • C min −1 . Light Scattering MeasurementLight scattering measurements were made with light scattering spectropho...

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Section: Resultsmentioning

confidence: 99%

Structural Relaxation and Refractive Index of Low-Loss Poly(methyl methacrylate) Glass

Tanio

2002

Polym J

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“…The calculated absorbance was represented by the oscillator strength divided by the van der Waals volume (nm3) of molecules. The van ver Waals volumes were calculated from the optimized geometries using the Slonimski's method [15], in which the van der Waals radii of atoms reported by Bondi [16] were used. [7] and calculated spectra of n-octane and 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol (HMP).…”

Section: Methodsmentioning

confidence: 99%

DFT Calculations of Photoabsorption Spectra in the VUV Region for Design of Photoresist Materials for 157 nm Lithography.

Ando

Fujigaya

Ueda

2002

J. Photopol. Sci. Technol.

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Time-dependent density functional theory (TD-DFT) calculations using the B3LYP hybrid functional were performed to investigate the transparencies of organic molecules and polymers in the vacuum ultraviolet (VUV) region. The calculated photoabsorption spectra obtained from the combination of geometry optimization using the 6-3110(d) basis set and subsequent calculations of transition energies and oscillator strengths using the 6-311++G(d,p) basis set agree well with the experimental spectra. This method is a useful to infer the transparency of polymers in the VUV region, and in particular helpful for design of photoresist materials for F2 lithography (157 nm). The transparencies of the model compounds relating to the representative polymer platforms were estimated, and the calculated spectra demonstrate the effectiveness of judicious introduction of -F and -CF3 groups in reducing optical absorption at the wavelength. In addition, the absorption spectra of model compounds having a sulfonyl fluoride (-S02F) and sulfonyl ester (-S020R) groups, which were proposed by the present authors as novel resist platforms, were calculated and compared with the experimental spectra of corresponding homopolymers.

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“…Going on the assumption of this hexagonal packing, the average volume per side chain was calculated from the spacing and is plotted in Figure 8. The van der Waals volume per side chain in each copolymer was estimated using values of respective groups reported in the literature 19 on the assumption of additivity. The difference between the measured and calculated volumes is the free volume 20 and is represented by a shaded area in Figure 8.…”

Section: Discussionmentioning

confidence: 99%

Dielectric Study on Cooperative Motion of Side Chain of Copoly(γ-methyl L-glutamate, γ-p-chlorobenzyl L-glutamate) in the Solid State

Yagihara

Hikichi

1981

Polym J

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ABSTRACT:Dielectric measurements on copoly(y-methyl L-glutamate, y-p-chlorobenzyl Lglutamate) [copoly(MLG, pCIBLG)] were performed in the frequency range of 0.03 to 300kHz and over the temperature range from -150 to + 130°C in order to study the side-chain motion. Two side-chain relaxations related respectively to MLG and pClBLG residues were observed. The results imply that there exists a cooperative motion of the side chains of poly( a-amino acid), though not as much as the main-chain motion of conventional amorphous polymers. The relaxation related to MLG residues is caused by clusters of MLG residues that are not affected by interactions between pCIBLG residues. KEY WORDSA number of poly(a-amino acid)s take on an ahelical form in the solid state.' It Is well known that side chains have great influence upon the conformation and physical properties of these polymers. 2 Many studies 2 -11 have been made on the side-chain motion of poly(a-amino acid), and it has been pointed out that a large scale displacement of the whole side chain occurs cooperatively.Dielectric 3 -5 and mechanical 2 • 6 · 7 measurements of poly(a-amino acid)s reveal a 'side-chain relaxation' caused by micro-Brownian motion throughout the side chain. It has also been reported that copoly(y-methyl L-glutamate, y-benzyl L-glutamate)s[copoly(MLG, BLG)s] take on the a-helical form in the solid state and show a single sidechain relaxation process brought about by a mechanism the same as that for the respective homopolymers.3 These facts support the proposition that the side-chain motion of poly( a-amino acid) occurs cooperatively, and thus seems similar to the mainchain motion of conventional amorphous polymers. This was also confirmed by a dielectric study on L-lysine, }'-benzyl Lglutamatc).4 No other dielectric studies on the sidechain motion of copoly(a-amino acid) have been reported.It seems, however, that the side-chain motion of a-helical poly( a-amino acid) is less cooperative than that of the main-chain motion of a conventional amorphous polymer, since the scale of the molecular rearrangement for the side-chain motion of the poly(a-amino acid) is probably smaller than the main-chain motion of the conventional amorphous polymer. No evidence for this has as yet been provided experimentally. In the present work, we carried out dielectric measurements on copoly-(y-methyl L-glutamate, y-p-chlorobenzyl L-giutamate)[copoly(MLG, pCIBLG)] in order to clarify the cooperativity of the side-chain motion of poly(a-amino acid). The dielectric behavior of PMLG 3 and PpCIBLG 5 is comparatively different, since the pCIBLG residue and its dipole moment are larger than those of the MLG residue. We examined the composition dependence of the dielectric behavior for these copolymers in detail.579

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The Packing of polymer molecules

Cited by 174 publications

References 8 publications

Structural Relaxation and Refractive Index of Low-Loss Poly(methyl methacrylate) Glass

Structural Relaxation and Refractive Index of Low-Loss Poly(methyl methacrylate) Glass

DFT Calculations of Photoabsorption Spectra in the VUV Region for Design of Photoresist Materials for 157 nm Lithography.

Dielectric Study on Cooperative Motion of Side Chain of Copoly(γ-methyl L-glutamate, γ-p-chlorobenzyl L-glutamate) in the Solid State

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