(396h) From 1D to 3D: Combined Experimental and Triple-Mode Sorption Modeling Study of Sorption and Transport in Materials

From 1D to 3D:
combined experimental and triple-mode sorption modeling study of sorption and transport
in materials

Hom N. Sharma, Yunwei Sun, and
Elizabeth A. Glascoe

Lawrence Livermore
National Laboratory

L288, 7000 East
Ave., Livermore, CA 94550

925-423-5368

sharma11@llnl.gov

Moisture sorption and transport in materials
is of great interest in wide range of applications (e.g. medicine to photovoltaics).(1-3) Moisture transport
can exacerbate hygrothermal aging and can significantly alter the chemical and
mechanical properties of materials. (3, 4) Over time, moisture concentration
can build up in the material or diffuse to the surrounding materials and
influence system functionality. Changes in chemical and physical properties
present many challenges affecting system reliability, including hydrolytic
degradation, corrosion of metal substrates, aging and material compatibility
issues, matrix cracking, micro-void generation, and interfacial delamination
causing irreversible damage. Further, geometric variation of materials in many
applications may impact the rate of moisture transport and material performance.
Therefore, a detailed understating of the moisture uptake and transport is crucial.

In this study, we investigate the moisture
transport phenomena and the effect of sample dimensions (i.e., size effect)
using a combined experimental and modeling approach. Very thin (i.e., membrane-like)
samples to centimeter-scale thick samples were considered to quantify the
effect of sample size. Multiple materials (for example: polymeric and
non-polymeric) are investigated over a wide range of temperatures (20-70) and relative
humidities (RH) (0-95%) to quantify the moisture transport mechanism. Gravimetric
type dynamic vapor sorption (DVS) experiments were employed to measure the
moisture uptake and used for the modeling. A reactive transport model is used
which includes a triple-mode sorption model(3) that includes
absorption, adsorption, and pooling of species, molecular diffusion, and
chemical reaction kinetics. Optimized parameters obtained from experimental
data from 1D sample were able to predict the moisture sorption profiles by
3D-type samples (see Fig. 1), which can reduce the parameter optimization and
simulation time significantly.

Fig 1:
Experiments and model predictions of dynamic moisture uptake by 3D Zircar RS1200
over a range of relative humidities at 70.

This
work performed under the auspices of the U.S. Department of Energy by Lawrence
Livermore National Laboratory under Contract DE-AC52-07NA27344.

LLNL-ABS-749688-DRAFT

References:

1. Harley
SJ, Glascoe EA, Lewicki JP, Maxwell RS. Advances in Modeling Sorption and
Diffusion of Moisture in Porous Reactive Materials. Chemphyschem.
2014;15(9):1809-20.

2. Harley
SJ, Glascoe EA, Maxwell RS. Thermodynamic Study on Dynamic Water Vapor Sorption
in Sylgard-184. J. Phys. Chem. B. 2012;116(48):14183-90.

3. Sun
YW, Harley SJ, Glascoe EA. Modeling and Uncertainty Quantification of Vapor
Sorption and Diffusion in Heterogeneous Polymers. Chemphyschem.
2015;16(14):3072-83.

4. Sharma, H. N., Harley, S. J., Sun, Y.
& Glascoe, E. A. Dynamic triple-mode sorption and outgassing

in materials. Sci. Rep.
2017; 7, 2942.