Breathability and Selectivity of Selected Materials for 

Protective Clothing 

by Eugene Napadensky and Yossef A. Elabd 

ARL-TR-3235 July 2004 

Approved for public release; distribution is unlimited. 
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Army Research Laboratory 

Aberdeen Proving Ground, MD 21005-5069 

ARL-TR-3235 July 2004 

Breathability and Selectivity of Selected Materials for 

Protective Clothing 

Eugene Napadensky and Yossef A. Elabd 

Weapons and Materials Research Directorate, ARL 

Approved for public release; distribution is unlimited. 
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Breathability and Selectivity of Selected Materials for Protective Clothing 

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6. AUTHOR(S) 

Eugene Napadensky and Yossef A. Elabd 

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14. ABSTRACT 

A series of materials was evaluated for its potential use as breathable (high water transport) barriers (low chemical agent transport) 

for military and civilian protective clothing apparel. The vapor transmission rates and effective permeabilities of water and dimethyl 

methyl phosphonate (DMMP) simulant for chemical agent (Sarin) through commercial and experimental polymeric membranes 

were measured using a modified American Society for Testing and Materials Method E-96-95. A variety of different materials from 

different companies was examined; unfortunately, some cannot be named due to proprietary restrictions. Materials examined 

included expanded PTFE, Nafion 117, sulfonated polystyrene-polyethylene-ran-polybutylene-polystyrene, sulfonated polystyrenepolyisobutylene-polystyrene, as well as four experimental and commercial membranes (A, B, C, and D). Results demonstrated that

laminated membrane A had the highest breathability (effective permeability of water vapor); however, an experimental laminated 

material C possessed the highest selectivity with sufficient breathability, where selectivity was defined as the ratio of water

permeability to DMMP permeability. Based on the results from this study, material C presented the greatest potential for a 

breathable barrier material for a chemical protective clothing application. 

15. SUBJECT TERMS

water vapor permeation, chemical and biological warfare, protective clothing, breathable barrier, polymer 

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Eugene Napadensky 

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iii

Contents 

List of Figures iv

List of Tables iv

Acknowledgments v

1. Introduction 1

2. Experimental 2

2.1 Materials..........................................................................................................................2 

2.2 Permeation Equipment ....................................................................................................3 

2.3 Membrane Preparation ....................................................................................................3 

2.4 Vapor Permeation Procedure...........................................................................................3 

2.4.1 Cap Loading ..........................................................................................................3 

2.4.2 Vapor Permeation..................................................................................................4 

3. Results and Discussion 5

3.1 Theory .............................................................................................................................5 

3.2 VTR and Peff ....................................................................................................................6 

3.3 Selectivity........................................................................................................................6 

4. Conclusion 10

5. References 11

Appendix A: Raw Data 13

Appendix B: Calculation Results 15

Appendix C: Sample Description 17

Distribution List 18
iv

List of Figures 

Figure 1. Schematic representing a cutaway of the cap-membrane assembly showing an 

open-top cap, membrane, and cored septa.................................................................................3 

Figure 2. Complete vial assembly used for vapor permeation experiments...................................4 

Figure 3. Weight loss during water vapor permeation experiments. ..............................................5 

Figure 4. Water vapor transmission rate.........................................................................................7 

Figure 5. Water-effective permeability results. ..............................................................................7

Figure 6. DMMP vapor transmission rate.......................................................................................8

Figure 7. DMMP-effective permeability results.............................................................................8 

Figure 8. Relative performance of materials based on effective permeability. ..............................9 

Figure 9. Selectivity of materials....................................................................................................9 

List of Tables 

Table 1. List of evaluated materials and their thickness.................................................................2 

Table A-1. Sample thickness and weight of vial assembly at a given time. Permeant is 

water. Conditions: 35 °C, 100% RH side A, and 10% RH side B.........................................13 

Table A-2. Sample thickness and weight of vial assembly at a given time. Permeant is 

DMMP. Conditions: 35 °C, 100% saturation side A, and 0% saturation side B. 

RH = 10% both sides. ..............................................................................................................14 

Table B-1. Calculation results.......................................................................................................15 
v

Acknowledgments 

This work was performed while Yossef A. Elabd held a National Research Associateship Award 

at the U.S. Army Research Laboratory. 
vi

INTENTIONALLY LEFT BLANK. 
1

1. Introduction 

Chemical and biological protective clothing technology remains a high priority among people 

responsible for the safety of U.S. military personnel. Not just from the obvious point of exposure 

to chemical or biological agents abroad and at home, but also from another, less often considered, 

but still important safety factor: breathability. Until recently the main goal in the development of 

chemical and biological protective clothing was to maximize protection. In the past, one of the 

more commonly used materials for this application was butyl rubber working on principle of total 

blockage. Butyl rubber is an effective barrier to most harmful agents at certain thicknesses, but it 

has certain disadvantages. Wearing garments manufactured from this material in combat or in 

other situations which involves physical activity is not practical because the lack of breathability of 

this material causes heat fatigue and exhaustion (1). A different approach for protection against 

chemical and biological threats is sorption materials. Protective suits such as the Military Oriented 

Protective Posture (MOPP) suit and the Joint Service Lightweight Integrated Suit Technology 

(JSLIST) work on principle of capturing toxic materials with fillers like activated carbon. JSLIST 

is more breathable, but it does not provide as much protection as butyl rubber. It is also relatively 

heavy, bulky, and working in the suit is limited to ~45 min/hr (2). 

A completely different approach to the problem of chemical and biological protection is the 

concept of semi-permeable membranes. That would be materials that allow passage of moisture 

(perspiration), but block harmful molecules and organisms. Materials like that will offer 

protection in the hostile environment without causing significant heat fatigue and exhaustion. A 

number of such semi-permeable membranes are being developed in industry and at the U.S. 

Army Research Laboratory (ARL). 

The scope of this work was to examine a series of semi-permeable membranes in order to 

evaluate their potential usefulness as a breathable, yet agent-resistant, material for military and 

civilian clothing. This study examines the permeation of water vapor and the permeation of 

dimethylmethylphosponate (DMMP) vapor through a variety of materials to determine the best 

candidates that are both breathable and protective. DMMP is chemically similar to the nerve 

agent Sarin (GB) and is often used to imitate the behavior of chemical agents when the usage of 

actual agents is cost prohibitive due to safety concerns. Materials examined in this study include 

some commercial materials as well as a number of experimental materials under development 

both at ARL and other laboratories. Due to proprietary restriction and other legal considerations, 

it was decided that four materials cannot be named and will be referred to as materials A, B, C, 

and D with manufacturers referred to by the same letter. 
2

2. Experimental 

2.1 Materials 

Materials evaluated in this study are listed in table 1. Sulfonated poly(styrene-isobutylenestyrene) (S-SIBS) at both 58 and 85 mole-percent sulfonation, referred to as S-SIBS-58 and 

S-SIBS-85 in table 1, respectively, was sulfonated at ARL and the details of this procedure can 

be found elsewhere (3). Mole-percent sulfonation is defined as moles of sulfonic acid per moles 

of styrene repeat unit and was determined by elemental analysis. The unsulfonated polymer was 

provided by Kuraray Co., Ltd., Tsukuba Research Laboratories, with the reported properties: 

30.84 weight-percent styrene, 0.95 specific gravity, Mw = 71,920 g/mol, Mn = 48,850 g/mol, and 

polydespersity index (PDI) = 1.47. Sulfonated poly(styrene-ethylene-ran-butylene-styrene) 

(S-SEBS) at both 59 and 93 mole-percent sulfonation, referred to as S-SEBS-59 and S-SEBS-93 

in table 1, respectively, was sulfonated at ARL and the general details of this procedure can be 

found elsewhere (4, 5). Unsulfonated poly(styrene-ethylene-ran-butylene-styrene) was provided 

by Kraton Polymers. S-SEBS-50 is a poly(styrene-ethylene-ran-butylene-styrene) sulfonated to 

45%–55% that was purchased from Sigma-Aldrich as a solution and cast into films at Natick 

Soldier Command Center. Other materials in this study included an expanded PTFE membrane, 

Nafion 117* (DuPont), and another four materials A, B, C, and D from corresponding 

companies. In addition, other chemicals used in these experiments were as follows: water 

(J. T. Baker, high-performance liquid chromatography [HPLC] grade), 

dimethylmethylphosphonate (Lancaster Synthesis, 97%), Drierite† (Anhydrous Calcium Sulfate, 

97%, W. A. Hammond Drierite Co.), toluene (EM Science, 99.5%), and hexanol (J. T. Baker). 

Table 1. List of evaluated materials and their thickness. 

Material Name Source and Manufacturer Sample Thickness 

(μm) 

S-SIBS-58 ARL 103–159 

S-SIBS-85 ARL 89–115 

S-SEBS-59 ARL 129–188 

S-SEBS-93 ARL 111–174 

S-SEBS-50 Aldrich 119–204 

A (cloth laminate) A 264–372 

Expanded PTFE Natick SCC 43–48 

B B 13–16 

C C 179–187 

D D 39–42 

Nafion 117 DuPont 181–186 

 *

 Nafion 117 is a registered trademark of DuPont. 

†

 Drierite is a registered trademark of W. A. Hammond Drierite Company. 
3

2.2 Permeation Equipment 

Equipment used for vapor permeation experiments consisted of a temperature-controlled oven 

with a nitrogen gas sweep passing through a Drierite-packed column. Aluminum trays with 

Drierite were also placed inside the oven to maintain a low-relative humidity (~10%). In 

addition, an analytical balance (precision = ± 0.0001 g) was used to measure weight loss and a 

digital micrometer was used to measure the thickness of each membrane (precision = ±1.2 μm). 

2.3 Membrane Preparation 

Membranes developed at ARL ( S-SIBS-58, S-SIBS-85, S-SEBS-59, S-SEBS- 93) were 

prepared by solution casting in Teflon* petri dishes at 2.5% w/v of polymer in 85/15 w/w toluene 

and hexanol. All membranes were cast in open air for 2 weeks, then annealed in a vacuum oven 

at 50 °C for 1 or 2 weeks to remove residual solvent. All other membranes were used as 

received. 

2.4 Vapor Permeation Procedure 

2.4.1 Cap Loading 

Twenty-mL vials, with open-top caps (VWR) and Teflon-lined septa with a 14-mm hole cut in 

the center of the septa to match the hole in the cap were used (figure 1). Membranes were cut 

into circles with a 22-mm diameter, the size of the original septa. The thickness of each 

individual membrane was measured with a digital micrometer. Membranes were placed inside 

the cap with the cored septa placed behind to provide an air tight seal. 

Figure 1. Schematic representing a cutaway of the capmembrane assembly showing an open-top cap, 

membrane, and cored septa.

 *

 Teflon is a registered trademark of DuPont. 

Cored septa

Open-top cap 

Membrane 
4

For samples A and C, the polymeric membranes which are laminated onto cloth were loaded into 

the cap assembly with the cloth side positioned toward the permeant for DMMP vapor 

permeation and positioned away from the permeant for water vapor permeation. 

2.4.2 Vapor Permeation 

Vapor permeation experiments were conducted based on the American Society for Testing and 

Materials (ASTM) E 96-95 (Standard Test Methods for Vapor Transmission of Materials) 

procedure (6). An oven, with nitrogen gas purge passed through a desiccant trap, was stabilized 

at 35 °C and 10% relative humidity (RH). Vials were filled with 10–15 mL of liquid (water or 

DMMP) and placed in oven to equilibrate for about 24 hr. Vials were removed, regular caps 

were replaced with membrane lined caps shown in figure 1. The total assembly weight was 

recorded, and the vials were placed back into the oven to initiate the experiments. The complete 

membrane and vial assembly is shown in figure 2. 

Figure 2. Complete vial assembly used for vapor 

permeation experiments. 

Vial weight, temperature, and humidity inside the oven were recorded every 24 hr until a 

sufficient amount of data was collected to determine constant rate of weight loss for each vial 

(steady-state). RH remained constant at 10% throughout the duration of the experiment. When 

using water as a permeant, the conditions were 100% RH on one side of the membrane (inside 

the vial) and 10% RH on the other side (outside the vial). The concentration gradient provided 

the driving force for vapor transport. Experiments with DMMP vapor were at 100% DMMP 

Cored septa

Open-top cap 

Membrane 

20 ml vial 

Permeant 
5

saturation (6.77-mm Hg) on one side of the membrane (inside the vial) and 0% DMMP on the 

other side or outside the vial. 

Three experiments were conducted for each membrane, and the values calculated for each 

membrane are the average and standard deviation of those experiments. 

3. Results and Discussion 

3.1 Theory 

Vapor transfer rate (VTR) is defined as steady state VTR per unit area and can be expressed as 

follows: 

(t A)

G VTR

∗ = , (1) 

where G is weight of penetrant, t is time, and A is cross-sectional area. For this experiment, the 

cross-sectional area is 0.000154 m2

 because the diameter is constant at 14 mm. G/t can be 

regressed from the steady state portion of the weight loss data vs. time, as shown in figure 3. 

20

21

22

23

24

25

26

27

28

29

30

0 25 50 75 100 125 150 175 200

Time (hr)

Vial weight (gr)

S-SIBS-58

S-SIBS-85

S-SEBS-59

S-SEBS-93

S-SEBS-50

Material A ( laminate)

Expanded PTFE

Material B

Material C ( laminate)

Material D

Nafion 117

Figure 3. Weight loss during water vapor permeation experiments.
6

After calculating G/t from the data, VTR can be obtained using equation 1. 

VTR provides transport rate for a given penetrant through a membrane. However, VTR does not 

account for the thickness of the membrane effectively. More specifically, VTR will have 

different values for the same material at different thicknesses. To accurately compare materials 

independent of the processing thickness, an effective permeability must be calculated. Effective 

permeability (Peff) can be expressed as: 

S*(P P )

L VTR P

1 2

eff

−

∗ = , (2) 

where S is the saturation vapor pressure at the test temperature (mm Hg), P1 is the partial 

pressure or relative humidity on the challenge side, P2 is partial pressure on the exit side, and L is 

the sample thickness (m). For laminated samples (materials A and C), L was taken to be 

thickness of the full system, cloth and all the layers of lamination. Saturation vapor pressure for 

water at 35 °C is 41.175-mm Hg (7) and for DMMP at 35 °C, it is 6.77-mm Hg. The DMMP 

vapor pressure was determined by interpolating from known values at 25 and 65 °C (8). 

3.2 VTR and Peff 

Figures 4 and 5 show water VTR and Peff results for all of the materials studied. Since 

breathability is one the key goals, it is tempting to concentrate on materials with a high water 

VTR. However, since VTR values do not account for sample thickness, a high VTR value does 

not necessarily signify sufficient breathability. Good examples include expanded PTFE, material 

B, and material D. All three samples have high VTRs (figure 4), but when their thicknesses are 

taken into consideration, their effective permeability, Peff, (breathability) is significantly lower 

than other materials (figure 5). 

Figures 6 and 7 show VTR and Peff results for DMMP, respectively. DMMP simulates the nerve 

agent Sarin, and the optimum material is one that minimizes DMMP transfer for good barrier 

properties against chemical agents. Figure 7 shows that materials B, C, and D have the lowest 

values of DMMP Peff and would provide the best protection against chemical agents. 

3.3 Selectivity 

The goal for chemical and biological defense is to identify materials that will provide sufficiently 

high water transport (breathability) to reduce heat fatigue, and sufficiently low DMMP transport 

to reduce personnel risk from harmful agents. The performance of these materials can be 

examined by plotting Peff (DMMP) vs. Peff (WATER), as shown in figure 8. 

An actual numerical value of ratio of effective permeabilities is defined as selectivity (α): 

eff (WATER)

eff (DMMP)

P

P

α = , (3) 
7

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

5,500

S-SIBS-58S-SIBS-85

S-SEBS-59S-SEBS-93S-SEBS-50

Material A

Expanded PTFE

Material B

Material CMaterial D

Nafion 117 

Water Vapor Transmission Rate ( g/m 2/day)

Figure 4. Water vapor transmission rate. 0

0.005

0.01

0.015

0.02

0.025

0.03

S-SIBS-58S-SIBS-85

S-SEBS-59S-SEBS-93S-SEBS-50

Material A

Expanded PTFE

Material BMaterial CMaterial D

Nafion 117 

Effective Permeability ( g / mmHg / m / day )

Figure 5. Water-effective permeability results. 
8

0

100

200

300

400

500

600

S-SIBS-58S-SIBS-85

S-SEBS-59S-SEBS-93S-SEBS-50

Material A

Expanded

PTFE

Material B

Material CMaterial D

Nafion 117

DMMP Vapor Transmission Rate ( g/m 2/day)

Figure 6. DMMP vapor transmission rate. 

0.000

0.005

0.010

0.015

0.020

0.025

S-SIBS-58S-SIBS-85

S-SEBS-59S-SEBS-93S-SEBS-50

Material A

Expanded

PTFE

Material B

Material CMaterial D

Nafion 117

DMMP Effective permeability ( g/mmHg/m/day)

Figure 7. DMMP-effective permeability results. 

where a high value would be desired for a breathable protective material. This is the slope of the 

trend line shown in figure 8. The upper left corner of this plot is where an ideal material for 

breathable protective clothing would be located. This corresponds to a very high water transport 

and simultaneously very low agent transport or a high selectivity. 
9

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0 0.005 0.01 0.015 0.02 0.025

Effective Permeability of DMMP vapor

Effective Permeability of water vapor

S-SIBS-58 S-SIBS-85

S-SEBS-59 S-SEBS-93

S-SEBS-50 Material A

Expanded PTFE Material B

Material C Material D

Nafion 117

Figure 8. Relative performance of materials based on effective permeability. 

Selectivity values for materials examined in these experiments are shown in figure 9. Selectivity 

does not account for actual amount of penetrant going through membrane. A material that has 

high values for effective permeation for both penetrants may have the same selectivity as 

0.0

1.0

2.0

3.0

4.0

5.0

6.0

S-SIBS-58S-SIBS-85

S-SEBS-59S-SEBS-93S-SEBS-50

Material A

Expanded PTFE

Material B

Material CMaterial D

Nafion 117

Selectivity

Figure 9. Selectivity of materials.
10

a material that has low values for both penetrants. Therefore, generally selectivity cannot be 

used as a final criteria, but rather should be used in conjunction with Peff (water vapor). 

However, in this study, the water vapor transport for all materials (figures 4 and 5) provide 

sufficient breathability, and therefore, materials with the highest selectivities have the desired 

properties for breathable protective clothing (9). Figure 9 shows that material C has a selectivity 

that is more than double compared to the other materials in this study. 

4. Conclusion 

In this study, the water vapor transmission rate, effective permeability, and selectivity of water 

vapor and DMMP vapor (simulant for chemical warfare agent) were measured for a variety of 

commercial and experimental candidate materials for evaluation as a breathable barrier for 

protective clothing. Material C has sufficient water vapor permeability (breathability) and a 

selectivity (5.12) that is more than double compared to the rest of the materials evaluated. If 

high selectivity is used as an indicator, then out of the materials evaluated in this study, this one 

has a good potential for use as a breathable barrier for protective clothing. Of course, there are 

still other factors that need to be considered, such as durability, price, weight, process ability, and 

other physical properties. Over all, this preliminary study indicates that further research on the 

synthesis and testing of new semi-permeable materials may produce more efficient breathable 

barriers not only protective clothing for the military, but also for apparel for a variety of other 

applications. 
11

5. References 

1. Lee, B. T.; Yang, T. W.; Wilusz, E. Moisture Effects on Isobutylene-Isoprene CopolymerBased Composite Barrier. Moisture Diffusion and Detection; Polymer Engineering and 

Science 1996, 36 (9), 1217. 

2. Siegrist, D. Chemical—Biological Warfare: Protective Measures. Jane’s Defence Weekly; 

17 April 2002. 

3. Elabd, Y. A.; Napadensky, E. Sulfonation and Characterization of Poly(styrene-isobutylenestyrene) Triblock Copolymers at High Ion-Exchange Capacities. Polymer 2004, 45, 

3037–3043. 

4. Weiss, R.; Sen, A.; Willis, C. L.; Pottick, L. A. Block Copolymer Ionomers: 1 Synthesis 

and Physical Properties of Sulphonated Poly(styrene ethylene/butylenes styrene). Polymer

1991, 32 (10). 

5. Elabd, Y. A.; Napadensky, E.; Sloan, J. M.; Crawford, D. M.; Walker, C. W. Triblock 

Copolymer Ionomers Membranes. Part I: Methanol and Proton Transport. Journal of 

Membrane Science 2003, 217, 227–242. 

6. ASTM E 96-95. Standard Test Methods for Vapor Transmission of Materials. Annu. Book 

of ATM Stand. 2002. 

7. Handbook of Chemistry and Physics; 66th Edition; CRC Press Inc.: Florida, 1985. 

8. The Merck Index. An Encyclopedia of Chemicals, Drugs, and Biologicals, 13th Ed; Merck 

and Co., Inc.: Whitehouse Station, NJ, 2001. 

9. Rivin, D. U.S. Army-SBCCOM, Natick, MA. Private communication, 2003.
12

INTENTIONALLY LEFT BLANK. 
13

Appendix A: Raw Data 

Table A-1. Sample thickness and weight of vial assembly at a given time. Permeant is water. Conditions: 

35 °C, 100% RH side A, and 10% RH side B. 

Water 

Exposure Time 

(hr) -> 

Thickness 

(μm) 

0 92 116 140 164 188 

S-SIBS-58 A1 109 25.81 23.7504 23.2428 22.7492 22.2435 21.7727 

A2 103 25.957 23.9543 23.4171 22.8883 22.3772 21.8976 

A3 124 30.95 28.0352 27.5758 27.1353 26.6892 26.1969 

S-SIBS-85 B1 102 26.935 24.5824 24.0451 23.4724 22.9038 22.3436 

B2 115 27.867 25.4099 24.8006 24.1878 23.5615 22.9138 

B3 89 26.175 23.8069 23.1506 22.5163 21.8649 21.2498 

S-SEBS-59 C1 180 27.649 25.7069 25.1955 24.6922 24.1822 23.6915 

C2 165 29.961 27.806 27.2735 26.7396 26.2033 25.6764 

C3 129 28.664 26.6218 26.1177 25.6013 25.0809 24.5677 

S-SEBS-93 D1 111 29.091 26.6406 25.9849 25.3156 24.6322 23.94 

D2 112 26.898 24.5245 23.8562 23.2132 22.5651 21.9528 

D3 174 27.6 25.4118 24.8014 24.1948 23.5794 22.9894 

S-SEBS-50 E1 189 26.503 24.8842 24.4613 24.036 23.6085 23.1898 

E2 194 26.608 24.9407 24.5096 24.0696 23.622 23.1756 

E3 204 27.161 25.5268 25.1007 24.6711 24.236 23.7949 

Material A 

(cloth 

laminate) 

F1 364 26.183 24.6887 24.2904 23.906 23.5152 23.1394 

F2 364 26.815 25.2925 24.8936 24.5012 24.1052 23.7171 

F3 372 28.211 26.703 26.3152 25.9268 25.5368 25.1536 

Expanded 

PTFE G1 48 26.865 24.0392 23.3022 22.5587 21.8149 21.0809 

G2 43 27.402 24.6028 23.8866 23.1629 22.4373 21.702 

G3 45 26.592 23.5748 22.7577 21.9776 21.1942 20.441 

Material B H1 13 26.956 25.1371 24.6523 24.1764 23.6977 23.2253 

H2 15 26.839 25.0188 24.5366 24.0597 23.5797 23.1042 

H3 13 26.614 24.7743 24.2444 23.7175 23.1852 22.6532 

Material C 

(on cloth) I1 179 27.936 26.6991 26.3784 26.0559 25.7303 25.3981 

I2 184 27.709 26.4423 26.0724 25.718 25.3606 25.0048 

I3 187 26.977 25.7415 25.3991 25.0632 24.7267 24.3935 

Material D J1 41 27.103 24.814 24.1824 23.5555 22.9306 22.3022 

J2 42 26.572 24.2886 23.6986 23.1076 22.5099 21.9051 

J3 40 27.657 25.2216 24.613 23.9864 23.3307 22.6518 

Nafion 117 K1 186 27.177 24.5714 23.7643 22.9908 22.2352 21.4656 

K2 183 26.973 24.4624 23.695 22.9318 22.1877 21.4259 

K3 185 29.103 26.7624 26.0163 25.2733 24.5473 23.8026 
14

Table A-2. Sample thickness and weight of vial assembly at a given time. Permeant is DMMP. Conditions: 

35 °C, 100% saturation side A, and 0% saturation side B. RH = 10% both sides. 

DMMP 

Exposure Time 

(hr) -> 

 Thickness 

(μm) 

0 90 114 138 162 186 258 

S-SIBS-58 A1 114 32.5163 32.4117 32.3768 32.3416 32.3083 32.2731 32.163 

A2 130 33.1398 33.0479 33.0171 32.9872 32.9583 32.9274 32.8347 

A3 159 32.9086 32.822 32.7908 32.7593 32.7295 32.6975 32.6007 

S-SIBS-85 B1 115 32.7154 32.5869 32.5411 32.4952 32.4505 32.4038 32.255 

B2 107 32.2355 32.1049 32.0636 32.0248 31.986 31.9456 31.8215 

B3 108 34.5352 34.4027 34.3624 34.323 34.2842 34.2436 34.1181 

S-SEBS-59 C1 165 32.7134 32.59 32.5537 32.5175 32.4824 32.4456 32.3322 

C2 188 33.5829 33.4583 33.4214 33.3851 33.3495 33.3123 33.1975 

C3 152 33.1566 33.0194 32.9802 32.9422 32.9055 32.8673 32.748 

S-SEBS-93 D1 115 32.2193 32.0597 32.0101 31.9621 31.9147 31.8659 31.7179 

D2 131 32.9339 32.7754 32.7288 32.6825 32.6374 32.59 32.4449 

D3 133 33.1807 33.034 32.9919 32.9501 32.9086 32.8653 32.7321 

S-SEBS-50 E1 144 32.6787 32.5383 32.4972 32.457 32.4175 32.3761 32.2486 

E2 119 33.4826 33.3235 33.2686 33.2148 33.1637 33.1118 32.9546 

E3 180 32.5887 32.4776 32.4425 32.4075 32.3732 32.337 32.228 

Material A 

(cloth laminate) F1 365 33.2753 33.0494 32.9914 32.9329 32.8754 32.8159 32.6303 

F2 368 33.3663 33.1483 33.092 33.0363 32.9812 32.9242 32.7448 

F3 371 32.9934 32.7797 32.7243 32.6706 32.6166 32.5611 32.3855 

Expanded PTFE G1 45 32.8536 32.5868 32.5196 32.4538 32.388 32.32 32.108 

G2 46 33.8087 33.5325 33.4637 33.396 33.3277 33.2573 33.0381 

G3 45 32.9828 32.6531 32.5782 32.5036 32.4297 32.3537 32.115 

Material B H1 13 33.9629 33.6801 33.6087 33.5396 33.472 33.4027 33.1841 

H2 16 33.0792 32.8333 32.7699 32.7085 32.6479 32.5856 32.3895 

H3 15 32.9225 32.6739 32.6076 32.5446 32.4814 32.417 32.2177 

Material C 

(on cloth) I1 186 33.1451 33.1308 33.1214 33.1104 33.1019 33.0923 33.0611 

I2 182 32.9224 32.8995 32.885 32.87 32.8578 32.8447 32.8026 

I3 183 32.7894 32.7692 32.7582 32.7444 32.7328 32.72 32.6809 

Material D J1 39 32.245 32.0685 32.022 31.9762 31.9306 31.8844 31.7422 

J2 42 32.7597 32.5995 32.5552 32.5125 32.47 32.4267 32.2918 

J3 41 32.7042 32.546 32.504 32.4625 32.4207 32.378 32.2468 

Nafion 117 K1 181 32.7303 32.5144 32.4481 32.3811 32.3144 32.2466 32.0345 

K2 182 33.4008 33.1927 33.131 33.0695 33.0076 32.9442 32.749 

K3 182 32.7772 32.5757 32.5145 32.454 32.3927 32.3305 32.1383 
15

Appendix B: Calculation Results 

Table B-1. Calculation results. 

Water DMMP 

Water VTR Effective Permeability DMMP VTR Effective 

Permeability 

g/m2 day STDEV (g/mmHg m day) g/m2 day STDEV (g/mmHg m day) 

Selectivity 

Av STDEV Av STDEV 

S-SIBS-58 3175 197.41 9.56E-03 3.16E-04 210.9 17.0 4.16E-03 5.67E-04 2.30 

S-SIBS-85 3955 271.09 1.09E-02 1.47E-03 277.6 25.7 4.52E-03 5.96E-04 2.41 

L-SEBS-59 3357 95.26 1.43E-02 2.38E-03 243.8 6.1 6.06E-03 5.84E-04 2.36 

S-SEBS-93 4168 218.46 1.48E-02 3.28E-03 300.8 18.7 5.60E-03 3.05E-04 2.64 

S-SEBS-50 2812 54.75 1.48E-02 7.09E-04 280.2 55.9 5.95E-03 2.41E-04 2.49 

Material A 

(cloth laminate) 2531 23.82 2.50E-02 3.67E-04 375.7 11.8 2.04E-02 4.97E-04 1.22 

Expanded PTFE 4864 194.73 5.97E-03 3.88E-04 467.1 28.6 3.13E-03 1.86E-04 1.91 

Material B 3217 198.03 1.18E-03 9.74E-05 430.5 25.1 9.26E-04 4.08E-05 1.27 

Material C (on 

cloth) 2203 110.61 1.09E-02 7.01E-04 78.6 12.8 2.13E-03 3.24E-04 5.12 

Material D 4038 158.23 4.46E-03 7.61E-05 288.0 12.7 1.73E-03 5.43E-05 2.58 

Nafion 117 4921 117.02 2.45E-02 6.28E-04 420.7 21.3 1.13E-02 5.41E-04 2.17 
16

INTENTIONALLY LEFT BLANK. 
17

Appendix C: Sample Description 

• S-SIBS-58: Sulfonated (58%) polystyrene-polyisobutylene-polystyrene. Solvent cast. 

Yellowish elastomeric film. Sulfonated and cast at the U.S. Army Research Laboratory 

(ARL). Sample thickness: 103–59 μm. 

• S-SIBS-85: Sulfonated (85%) polystyrene-polyisobutylene-polystyrene. Solvent cast. 

Yellowish elastomeric film. Sulfonated and cast at ARL. Sample thickness: 89–115 μm. 

• S-SEBS-59: Sulfonated (59%) polystyrene-polyethylene-ran-polybutylene-polystyrene. 

Solvent cast. Yellowish elastomeric film. Sulfonated and cast at ARL. Sample thickness: 

129–188 μm. 

• S-SEBS-93: Sulfonated (93%) polystyrene-polyethylene-ran-polybutylene-polystyrene. 

Solvent cast. Yellowish elastomeric film. Sulfonated and cast at ARL. Sample thickness: 

111–174 μm. 

• S-SEBS-50: Sulfonated (45%–55%) polystyrene-polyethylene-ran-polybutylenepolystyrene. Purchased from Aldrich, solvent cast at Natick SCC. Yellowish elastomeric 

film. Sample thickness: 119–204 μm. 

• Material A: Three-layer laminated cloth, woodland camouflage on external side, and olive 

green on internal. Manufactured by company A, obtained from Natick SCC. Sample 

thickness (total): 264–372 μm. 

• Expanded PTFE: Thin white film. Obtained from Natick SCC. Sample thickness: 

43–48 μm. 

• Material B: Whiteish, semi-transparent polyester/polyether membrane manufactured by 

company B. Obtained from Natick SCC. Sample thickness: 13–16 μm. 

• Material C (cloth laminate): Experimental laminate manufactured by company C. 

Woodland camouflage cloth on external sid and white polymeric film on internal. Sample 

thickness (total): 179–187 μm. 

• Material D: Experimental membrane manufactured by company D. Yellowish elastomeric 

film. Sample thickness: 39–42μm. 

• Nafion 117: Perfluorinated membrane, hydrogen ion form. Yellowish elastomeric film. 

Manufactured by DuPont. Sample thickness: 181–186 μm.
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