Why is it that during spinodal decomposition one refers to the diffusion of atoms as uphill diffusion?

However, since ∂ 2 Δ G m / ∂ φ B 2 is negative within the spinodal region, D must also be negative. Therefore phase separation must occur by a diffusional flux against the concentration gradient in the spinodal region. This process is sometimes referred to as ‘uphill’ diffusion.

What is spinodal?

In thermodynamics, the spinodal is the limit of stability of a solution, denoting the boundary of absolute instability of a solution to decomposition into multiple phases. Outside of the curve, the solution will be at least metastable with respect to fluctuations.

What is Binodal line?

In thermodynamics, the binodal, also known as the coexistence curve or binodal curve, denotes the condition at which two distinct phases may coexist. In general, the binodal is defined by the condition at which the chemical potential of all solution components is equal in each phase.

What are spinodal lines?

The locus of these points (the inflection point within a G-x or G-c curve, Gibbs free energy as a function of composition) is known as the spinodal curve. For compositions within this curve, infinitesimally small fluctuations in composition and density will lead to phase separation via spinodal decomposition.

What is binodal line?

How do you find the binodal curve?

To complete the binodal curve, an indirect method is attempted: the repetitive drop-wise addition of the PEG solution to the salt solution until the detection of a cloudy solution, followed by the drop-wise addition of distilled water until the detection of a monophasic region (clear and limpid solution).

What is binodal curve in liquid liquid extraction?

1, the binodal curve TCB divides a region of component concentrations that will form two immiscible aqueous phases (above the curve) from those that will form one phase (below the curve). This curve represents the separation between the two im- miscible phases.

What is spinodal decomposition?

• Spinodal decomposition is a mechanism by which a solution of two or more components can separate into distinct phases with distinctly different chemical compositions and physical properties.

What is a spinodal curve in chemistry?

Spinodal Curve: A curve that separates a metastable region from an unstable region in the coexistence region of a binary mixture. Above the spinodal curve the process of moving towards equilibrium occurs by droplet nucleation, while below the spinodal curve there are periodic modulations of the order parameter,

What is the binodal line?

The binodal line is the separation between the single- and two-phase region.

How to calculate the binodal of a polymer-polymer interaction parameter?

For a symmetrical polymer blend, i.e. for a blend of two polymers with equal chain length, rP1= rP2= r, the expression for the binodal reads: χ1,2· r= ln[φP2/ φP1 ] / (1 – 2φP1) where φP1and φP2 are the volume fractions of the two polymers and χ1,2is the polymer-polymer interaction parameter.