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Plot SEC Conformation Data

Source: R/plot-functions.R
plot_sec_conformation.Rd

Creates conformation plots showing structure-MW relationships from multi-detector SEC data (Mark-Houwink plots, Rg-MW scaling).

Usage

plot_sec_conformation(
  data,
  type = c("rg_mw", "eta_mw", "rh_mw"),
  mw_col = "mw",
  y_col = NULL,
  sample_id = NULL,
  show_fit = TRUE,
  show_exponent = TRUE,
  compare_linear = NULL,
  ...
)

Arguments

data

A data frame containing SEC results with MW and conformation data (Rg, intrinsic viscosity).

type

Type of conformation plot:

  • "rg_mw": Radius of gyration vs molecular weight (default)

  • "eta_mw": Intrinsic viscosity vs molecular weight

  • "rh_mw": Hydrodynamic radius vs molecular weight

mw_col

Name of molecular weight column. Default is "mw".

y_col

Name of y-axis column. If NULL, auto-detected based on type.

sample_id

Column name containing sample identifiers.

show_fit

Logical. Show power-law fit line? Default is TRUE.

show_exponent

Logical. Annotate slope/exponent on plot? Default is TRUE.

compare_linear

Data frame with linear reference polymer for branching comparison. Should have same structure as main data.

...

Additional arguments passed to ggplot2::geom_point().

Value

A ggplot2 object.

Details

Conformation plots reveal polymer architecture:

Rg-MW (radius of gyration): Log-log slope indicates conformation:

  • 0.33: Compact sphere

  • 0.5-0.6: Random coil (linear polymer in good solvent)

  • 1.0: Rigid rod Branched polymers show reduced Rg at same MW compared to linear.

eta-MW (Mark-Houwink): The relationship [eta] = K * M^a where:

  • K and a are Mark-Houwink parameters

  • a is approximately 0.5-0.8 for typical polymers

  • Branched polymers show lower [eta] at same MW

See also

Other sec-visualization: autoplot.sec_results(), plot_sec(), plot_sec_calibration(), plot_sec_chromatogram(), plot_sec_composition(), plot_sec_multidetector(), plot_sec_mwd(), sec_results()

Examples

if (FALSE) { # \dontrun{
# Rg-MW plot from MALS data
plot_sec_conformation(processed_data, type = "rg_mw")

# Mark-Houwink plot
plot_sec_conformation(processed_data, type = "eta_mw")

# Compare branched to linear reference
plot_sec_conformation(
  branched_data,
  compare_linear = linear_reference
)
} # }