What is the interaction parameter?
Definition. The interaction parameter gives a measure of the interaction between molecules, for example, surfactants or polymers, or between the molecule and the medium in which it is dissolved. Various interaction parameters can be described as follows: (1) surfactant mixtures with no net interaction.
What is Flory Huggins equation?
The Flory–Huggins equation deals with molecules that are similar chemically, but differ greatly in length. The model is based on the idea that the chain elements arrange themselves randomly on a three-dimensional structure.
What is the relation between the interaction parameter?
1. What is the relation between the interaction parameter, ‘b’, and atomic radius, R, for the Pair Production? Explanation: If b < R, the photon is directly converted into an electron-positron pair, known as pair production. If b > R, it means the interaction parameter is greater than the atomic radius.
What is Flory temperature?
The unique temperature at which the attractions and repulsions of a polymer in a solution cancel each other. It is analogous to the Boyle temperature of a nonideal gas. A polymer solution at the Flory temperature is called a theta (θ) solution.
What is Flory interaction parameter?
Abstract: The Flory–Huggins χ parameter describes the excess free energy of mixing and governs phase behavior for polymer blends and block copolymers. For chemically-distinct nonpolar polymers, the value of χ is dominated by the mismatch in cohesive energy densities of the monomers.
How is Flory Huggins parameter calculated?
However, this is often not the case; χ is usually a function of both temperature and composition (polymer concentration). where B describes the temperature dependence of χ….Polymer-Solvent Interaction Parameter. at Infinite Dilution. (1)
| Polymer | Solvent | χ∞ |
|---|---|---|
| Polystyrene | Benzene | 0.465 |
| Poly(vinyl alcohol) | Water | 0.494 |
What is the Flory exponent?
Abstract. In the present paper, considering oriented polymers interacting with a background tangent field u, the Flory exponent ν is self-consistently calculated to be ν=3/(d+2) for d≤4 and ν=1/2 for d≥4 using the renormalization theory for turbulent transport. The results of this paper agree with that of Kamien [J.
What is Compton shift Mcq?
Explanation: when a photon collides with an electron at rest, the photon gives its energy to the electron. therefore the scattered photon will have higher wavelength compared to the wavelength of the incident photon. this shift in wavelength is called compton shift.
Which is the correct expression of Braggs equation?
Explanation: Bragg’s law gives us the relation between the wavelength of the incident X-ray and the angle of incidence. The expression is: nλ = 2dsinθ.
What are theta conditions?
If a solvent is precisely poor enough to cancel the effects of excluded volume expansion, the “theta (θ) condition” is satisfied. For a given polymer-solvent pair, the theta condition is satisfied at a certain temperature, called the “theta (θ) temperature.” A solvent at this temperature is called a theta solvent.
What is Huggins constant?
The constant kH is termed the Huggins constant and has values ranging from 0.3 in good solvents to 0.5 in poor solvents. It contains information about hydrodynamic and thermodynamic interactions between coils in solution.
How do you find Flory with exponents?
In the present paper, considering oriented polymers interacting with a background tangent field u, the Flory exponent ν is self-consistently calculated to be ν=3/(d+2) for d≤4 and ν=1/2 for d≥4 using the renormalization theory for turbulent transport.
What is Flory radius?
The Flory radius, RF, is defined by the random walk law, The Flory radius applies, for the most part, in the melt. When a polymer is put in solution with an organic solvent, such as polystyrene in gasoline, the coil expands to a larger size than the size reflected by equation 3.
What is meant by Compton shift?
Definition of Compton shift : the increase in X-ray or gamma-ray wavelength resulting from the transfer of energy that accompanies the scattering of photons in the Compton effect.
What is significance of Compton shift?
The greatest significance of the Compton effect is that is to provides final and deciding proof for Planck-Einstein’s visualization of the quantum nature of radiation. The particle nature of light was established after the discovery of the Compton effect.
What is Bragg’s law explain?
Bragg law, in physics, the relation between the spacing of atomic planes in crystals and the angles of incidence at which these planes produce the most intense reflections of electromagnetic radiations, such as X-rays and gamma rays, and particle waves, such as those associated with electrons and neutrons.
What is an athermal solvent?
In an athermal solvent, the interactions between solvent and polymer repeat units are equal to those between solvent molecules and polymer segments. Thus, the enthalpy of mixing is zero.
How is Kuhn length calculated?
For worm-like chain, Kuhn length equals two times the persistence length.
What are Huggins and Kraemer constant for polymer viscosity?
Huggins’ constant, k′, and Kraemer’s, k′′, are related by: k′ − k′′ = 0.5. Thus, since k′ is often between 0.6 and 0.8, k′′ will often lie between 0.1 and 0.3. (Kamide K, Dobashi T (2000) Physical chemistry of polymer solutions. Elsevier, New York; Huggins ML (1958) Physical chemistry of high polymers.