Flow Induced Crystallization: General description

Purpose

Data Files

  • The first line of the file should contain the sample parameters separated by semi-colons (;). It may contain any number of parameters which will be read and saved as file-parameter in RepTate. In unit-aware applications, a file parameter value may also include an explicit unit, for example Mw=1131 Da;T=25 ºC;gdot=0.1 1/s;.

  • Then the data columns should appear, separated by spaces or tabs.

  • In unit-aware applications, column headers may include units in square brackets or parentheses, for example t [min] or G' [kPa]. See Units for the supported units and current limitations.

.shearxs extension

Text files with .shearxs extension should be organised as follows:

  • .shearxs files should contaion at least the parameter values for the:

    1. shear rate, \(\dot\gamma\)

    2. shear end time, \(t\)-stop

    3. temperature, \(T\)

  • 5 columns separated by spaces or tabs containing respectively:

    1. time, \(t\),

    2. shear stress growth function, \(\sigma^+(t)\),

    3. nucleation rate, \(\dot N(t)\),

    4. crystal fraction, \(\phi_X(t)\),

    5. nucleation density, \(N(t)\),

Other columns will be ignored. A correct .shearxs file looks like:

gdot=0.1;tstop=50.0;T=0.0;
t               sigma_xy        Ndot        phi_X           N
1.437E+00       1.411E+02       5.103E-09       3.227E-08       1.001E-05
1.751E+00       1.709E+02       1.358E-08       5.772E-08       1.001E-05
2.134E+00       2.065E+02       4.283E-08       1.034E-07       1.002E-05
2.600E+00       2.486E+02       1.623E-07       1.858E-07       1.006E-05
3.168E+00       2.978E+02       7.418E-07       3.349E-07       1.028E-05
...         ...         ...         ...         ...

Views

log(eta(t))

Ndot(t) [log-log]

N(t) [log-log]

phiX(t) [log-log]

Ndot(t) [log-lin]

Nucleation rate as a function of time on log axis \(\dot{N}(t)\) vs time \(t\)

N(t) [log-lin]

Nucleation density as a function of time on log axis \(N(t)\) vs time \(t\)

phiX(t) [log-lin]

Crystal fraction as a function of time on log axis \(\\phi_X(t)\) vs time \(t\)

eta(t))

log(sigma(gamma))

sigma(gamma)

log(sigma(t))

sigma(t)

Flow Curve

Steady Nucleation

The Crystal application views use the columns of the loaded crystallisation file. For the .shearxs files described above, the columns are time, transient stress, nucleation rate, crystal fraction, and nucleation density. The flow rate is taken from the file parameters and is used to calculate transient viscosity and strain.

Use log(eta(t)) or eta(t) to inspect the transient viscosity, \(\eta^+(t)=\sigma^+(t)/\dot\gamma\). The logarithmic view calculates \(\log_{10}(t)\) and \(\log_{10}(\eta^+)\) explicitly; the eta(t) view plots the same quantity using logarithmic axes by default.

Use the Ndot(t), N(t), and phiX(t) views to follow the crystallisation quantities as functions of time. Ndot(t) shows the nucleation rate, N(t) shows the nucleation density, and phiX(t) shows the crystal fraction. Each quantity is available with log-log and log-lin scaling so that early-time and late-time behaviour can be inspected without changing the data.

Use sigma(t) and log(sigma(t)) to inspect the transient stress as a function of time. sigma(t) [log-lin] keeps the stress on a linear axis while using a logarithmic time axis. Use sigma(gamma) and log(sigma(gamma)) to plot the same transient stress against strain, where the strain is computed from time multiplied by the flow rate.

Flow Curve and Steady Nucleation provide one point per file. Flow Curve plots the final stress value against the flow rate, and Steady Nucleation plots the final nucleation-rate value against the flow rate. These views are useful when several files at different flow rates are loaded in the same dataset.

Logarithmic views require positive time and positive values of the plotted quantity. The steady views use the last row of each file as the steady-state estimate, so they assume that the imported data extend far enough in time for the final value to be representative.