Diffusion of oxygen in cork.

Area of Science:

• Materials Science
• Chemical Engineering
• Physical Chemistry

Background:

• Cork is a natural material with variable properties.
• Understanding oxygen diffusion in cork is crucial for its applications, especially in wine stoppers.
• Previous methods for determining oxygen diffusion in cork were time-consuming.

Purpose of the Study:

• To measure the effective oxygen diffusion coefficient (D(eff)) in raw cork.
• To develop and validate a method for predicting long-term oxygen transfer from short-term measurements.
• To compare experimental results with theoretical models.

Main Methods:

• A homemade manometric device was used to measure oxygen pressure changes over time.
• Fick's law was applied to transient and steady-state conditions using numerical and analytical models.
• Measurements were conducted on 3 mm thick cork wafers at 298 K.

Main Results:

• The harmonic average D(eff) for 3 mm cork wafers was 1.1 × 10⁻⁹ m²/s, with significant variation.
• Extrapolation to a 48 mm cork stopper yielded a mean D(eff) of 1.6 × 10⁻⁹ m²/s.
• Short-term measurements on thin wafers accurately predicted diffusion in thicker samples.

Conclusions:

• A reliable method was established to determine oxygen diffusion in cork using short-term experiments.
• This method significantly reduces the time required to assess oxygen transfer properties of cork stoppers.
• The findings facilitate better quality control and material selection for cork-based products.