Multilayer Packaging Barrier (2D): Diffusion-Resistance Stack

Real barrier films are laminates — thin layers of different polymers (and sometimes aluminium foil) stacked to keep oxygen out and extend shelf life. This simulator renders the stack two ways at once: a true-to-scale 2D cross-section you can drag to resize, and a resistor-ladder chart that shows which layer actually dominates the diffusion resistance. It computes oxygen transmission rate from the same resistance-in-series model packaging engineers use, and scores the resulting structure against mono-material recyclability rules used in Environmental Product Declarations and extended-producer-responsibility schemes. Add barrier layers to push shelf life up and watch the recyclability score collapse; strip back to a single polymer and watch the reverse. The core packaging-design dilemma — shelf life versus circularity — happens live under your own sliders and drags.