Success Story

Diaper Dynamics

Diaper Dynamics

Los Alamos National Laboratory’s expertise in nuclear weapons helped P&G engineer a better diaper.

Yes, really.

Twenty-five years ago, P&G approached Los Alamos with a unique problem: how do you keep fluid away from baby’s skin? It doesn’t seem like a question a nuclear weapons laboratory can answer, but in fact, Los Alamos has unique expertise in how fluids move. Why? Because to understand what happens after a nuclear explosion occurs requires scientists to understand how the materials around it behave. The temperature surrounding a nuclear detonation becomes so high that solids melt into liquid. Los Alamos uses computational fluid dynamics (CFD) to understand complex mechanisms of liquid flow and how to manipulate it.

P&G wanted to capitalize on that expertise to build a better diaper. Thanks to a partnership between Los Alamos National Laboratory and P&G, researchers have applied and refined complex CFD models to the manufacturing process of diapers and to study the flow of fluids in fibrous materials. In particular, the team wanted to know what characteristics of fibrous material can increase the efficiency of holding fluid next to the diaper as opposed to next to the skin. Los Alamos studied the morphology of the fibrous material in diapers and calculated the flow of fluids through that material. The analysis gave a series of results that describe how the fluid is distributed and where it goes depending on the density of the fibers and on their absorbing characteristics.

So P&G (and parents) got a better diaper. Meanwhile, this project’s validation of the CFD models contributed valuable inputs to strengthen analyses in the core nuclear science programs—which in turn helped strengthen critical national security programs.