Effect of isotope substitution on the viscosity of water-methanol mixtures at 25.degree.C

Wolf, D.; Kudish, A. I.

doi:10.1021/j100445a027

Cited by 21 publications

(8 citation statements)

References 6 publications

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“…Besides, we also calculated the volume of polarization unit (PNIPAM chain) from the Stokes‐Einstein‐Debye equation, which describes the relation between the relaxation time τ of the polarization unit, mixed solvent viscosity η and the volume V .

τ = \frac{3 V η}{k_{B} T}

where

k_{B}

is the Boltzmann constant and T is temperature in K .…”

Section: Resultssupporting

confidence: 54%

Cononsolvency of poly(N‐isopropylacrylamide) in methanol aqueous solution—insight by dielectric spectroscopy

Yang

Zhao

2017

J Polym Sci B Polym Phys

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Both water and methanol are good solvents for poly(N‐isopropylacrylamide) (PNIPAM), while PNIPAM does not dissolve in their mixed solvents, this phenomenon is called cononsolvency. Cononsolvency is closely related to many phenomena in life but so far, its mechanism is still controversial. In this work, the dielectric behavior of PNIPAM methanol aqueous solution was studied in the frequency of 40Hz–40GHz. From lower frequency to higher frequency, four relaxations were found. They are, respectively, from global chain motion, local motion of backbone, motion of side chain group, and the dipole orientation of the solvent molecule. The solvent dependence of dielectric parameters for the chain motion implied that the PNIPAM chain has undergone the coil‐globule‐coil transition. Dielectric analysis to microwave frequency showed that the volume of the bound solvent units on PNIPAM chain increases with the increasing methanol concentration, which suggested that the structure of solvation units bound on PNIPAM side chains undergo a changing process experience from water to water‐methanol cluster to the ternary methanol cluster. This work reveals the structure and dynamics of the PNIPAM chain and the solvent unit that involved in the solvation of PNIPAM, and provides some new insight into the cononsolvency phenomenon. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1227–1234

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τ = \frac{3 V η}{k_{B} T}

where

k_{B}

is the Boltzmann constant and T is temperature in K .…”

Section: Resultssupporting

confidence: 54%

Cononsolvency of poly(N‐isopropylacrylamide) in methanol aqueous solution—insight by dielectric spectroscopy

Yang

Zhao

2017

J Polym Sci B Polym Phys

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“…Given the reported viscosities, 27,28 the average radius of the molecule as determined from the density and the molecular The legend shows corresponding samples as coded in Table 1.…”

Section: Resultsmentioning

confidence: 99%

Singlet lifetime measurements in an all-proton chemically equivalent spin system by hyperpolarization and weak spin lock transfers

Zhang

Basu

Canary

et al. 2015

Phys. Chem. Chem. Phys.

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Hyperpolarized singlet states provide the opportunity for polarization storage over periods significantly longer than T1. Here, we show how the singlet state in a chemically equivalent proton spin system can be revealed by a weak power spin-lock. This procedure allowed the measurement of the lifetimes of the singlet state in protic solvents. The contributions of different intra- and intermolecular relaxation mechanisms to singlet lifetimes are investigated with this procedure.

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“…The viscosity curves of aqueous solutions of diamines are found to be typical of those of aqueous solutions of amphiphiles, such as, alcohols, amines, amides etc. [8][9][10][11][12][13][14]. The rapidly ascending part of the viscosity may be ascribed primarily to two effects: (i) hydrophilic effect and (ii) hydrophobic hydration.…”

Section: Resultsmentioning

confidence: 99%

Viscosity of aqueous solutions of some diamines

Saleh

Akhtar

Ahmed

2004

Physics and Chemistry of Liquids

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Viscosities of the systems, ethylenediamine (ED) þ water (W), 1,2-diaminopropane (DAP) þ W, trimethylenediamine (TMD) þ W and N,N-dimethyltrimethylenediamine (DMTMD) þ W, have been measured for the whole range of composition at temperatures ranging from 303.15 to 323.15 K. The viscosities have been plotted against the mole fraction of diamines, showing some common characteristics for all the systems. On addition of diamines to water viscosities rise up very rapidly and pass through maxima. Following the maxima viscosities decline quite rapidly and monotonously up to about 0.6 mole fraction of diamines, which then fall down rather slowly. The hydrophobic and hydrophilic effects are considered responsible for the ascending part of viscosities in water-rich region, although the former is thought to be much more predominant than the latter. The height of viscosity maxima and their shifting to more water-rich region have been explained preferentially in terms of the hydrophobic effect. The declining part of viscosities is thought to be due to continuous destruction of cage structures formed by hydrophobic interaction. The excess viscosities have been calculated and plotted against mole fractions of diamines. The characteristics of excess viscosities have been explained by the same reasonings as used to explain viscosities.

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Effect of isotope substitution on the viscosity of water-methanol mixtures at 25.degree.C

Cited by 21 publications

References 6 publications

Cononsolvency of poly(N‐isopropylacrylamide) in methanol aqueous solution—insight by dielectric spectroscopy

Cononsolvency of poly(N‐isopropylacrylamide) in methanol aqueous solution—insight by dielectric spectroscopy

Singlet lifetime measurements in an all-proton chemically equivalent spin system by hyperpolarization and weak spin lock transfers

Viscosity of aqueous solutions of some diamines

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