S1

Supporting Information

Self Assembled, Sulfonated Pentablock Copolymer Cation Exchange Coatings for

Membrane Capacitive Deionization

Amit Jain1,2, Cierra Weathers1,2, Jun Kim2,3, Matthew D. Meyer5, Shane Walker2,6,

Qilin Li2,3,, Rafael

Verduzco1,2,4,*

1Department of Chemical and Biomolecular Engineering, Rice University, MS 362, 6100 Main

Street, Houston, USA

2NSF Nanosystems Engineering Research Center Nanotechnology-Enabled Water Treatment,

Rice University, MS 6398, 6100 Main Street, Houston, USA

3Civil and Environmental Engineering, Rice University, MS 319, 6100 Main Street, Houston,

USA

4Material Science and Nanoengineering, Rice University, MS 325, 6100 Main Street, Houston,

USA

5Shared Equipment Authority, Rice University, MS 100, 6100 Main Street, Houston, USA

6Civil Engineering, The University of Texas at El Paso, 500 W University Avenue, El Paso,

Texas, USA

Correspondence to: rafaelv@rice.edu

Keywords: Capacitive Deionization, Membrane, Sulfonated pentablock copolymer, Activated

Carbon, Desalination.

Electronic Supplementary Material (ESI) for Molecular Systems Design & Engineering.This journal is © The Royal Society of Chemistry 2019

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Figure/Table

Page

Figure S1. The figure shows the two-chamber setup for salt permeability tests. Freestanding polymer films were inserted between the two chambers and test solution was added to the left chamber and deionized water to the right chamber along with the conductivity sensor.

S3

Figure S2. Five stable desalination cycles plotting effluent concentration vs. time for (a) to (c) varying polymer sulfonation level and (d) to (i) casting solvent polarity.

S4

Figure S3. Data for 50 cycles plotting salt adsorption capacity vs. cycle number for (a) to (c) varying polymer sulfonation level and (d) to (i) casting solvent polarity.

S5

Figure S4. Data for 50 cycles plotting charge efficiency vs. cycle number for (a) to (c) varying polymer sulfonation level and (d) to (i) casting solvent polarity.

S6

Figure S5. Additional TEM images of the polymer films when casted form the casting solvent blend with 50 wt % n-propanol and (a) IEC 1.0 (b) IEC 1.5, and (c) IEC 2.0. TEM images of all the three samples indicate an inverted micellar morphology.

S7

Table S1. Polymer casting solution sample information, water uptake and salt permeability data of the freestanding polymer films, salt adsorption capacity and charge efficiency MCDI performance data for the various polymer coated electrodes.

S7

Figure S6. Additional TEM images obtained through longer staining. The figure demonstrates the morphology of the polymer films when cast form the casting solvent blend with (a) 10 wt % n-propanol, (b) 20 wt % n-propanol, (c) 30 wt % n-propanol, (d) 40 wt % n-propanol, (e) 50 wt % n-propanol, and (f) 60 wt % n-propanol. The black color particles in figure “a,c,d,f” are the artifacts due to crystallization of the staining agent on the membrane films.

S8

S3

Figure S1. The figure shows the two-chamber setup for salt permeability tests.

Freestanding polymer films were inserted between the two chambers and test solution

was added to the left chamber and deionized water to the right chamber along with the

conductivity sensor.

SaltSolutionDonorCell

DIWaterReceiverCell

MembraneConductivity

Probe

S4

Figure S2. Five stable desalination cycles plotting effluent concentration vs. time for (a)

to (c) varying polymer sulfonation level and (d) to (i) casting solvent polarity.

2

6

10

14

18 IEC 1.0

2

6

10

14

18 IEC 1.5

2

6

10

14

18

0 30 60 90 120 150

IEC 2.0

Time(min)

Efflu

entC

oncentratio

n(m

M)

2

6

10

14

18 10% np

2

6

10

14

18 20% np

2

6

10

14

18 30% np

2

6

10

14

18 40% np

2

6

10

14

18 50% np

2

6

10

14

18

0 30 60 90 120 150

60% np

Time(min)

Efflu

entC

oncentratio

n(m

M)

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

S5

Figure S3. Data for 50 cycles plotting salt adsorption capacity vs. cycle number for (a)

to (c) varying polymer sulfonation level and (d) to (i) casting solvent polarity.

5

8

11

14 50%np5

8

11

14 40%np

5

8

11

14

0 10 20 30 40 50

60%np

5

8

11

14 30%np5

8

11

14 20%np5

8

11

14 10%np(d)

(e)

(f)

(g)

(h)

(i)

CycleNumber

SaltAd

sorptio

nCa

pacity(m

g/g)

5

8

11

14 IEC1.55

8

11

14 IEC1.0

5

8

11

14

0 10 20 30 40 50

IEC2.0

(a)

(b)

(c)

CycleNumber

SaltAd

sorptio

nCa

pacity(m

g/g)

S6

Figure S4. Data for 50 cycles plotting charge efficiency vs. cycle number for (a) to (c)

varying polymer sulfonation level and (d) to (i) casting solvent polarity.

70

80

90

10050%np

70

80

90

10040%np

70

80

90

100

0 10 20 30 40 50

60%np

70

80

90

10030%np

70

80

90

10020%np

70

80

90

10010%np(d)

(e)

(f)

(g)

(h)

(i)

CycleNumber

ChargeEfficiency(%

)

70

80

90

100IEC1.5

70

80

90

100IEC1.0

70

80

90

100

0 10 20 30 40 50

IEC2.0

(a)

(b)

(c)

CycleNumber

ChargeEfficiency(%

)

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Figure S5. Additional TEM images of the polymer films when casted form the casting

solvent blend with 50 wt % n-propanol and (a) IEC 1.0 (b) IEC 1.5, and (c) IEC 2.0. TEM

images of all the three samples indicate an inverted micellar morphology.

Table S1. Polymer casting solution sample information, water uptake and salt

permeability data of the freestanding polymer films, salt adsorption capacity and charge

efficiency MCDI performance data for the various polymer coated electrodes as well as

the MCDI system with the commercial ion-exchange membranes.

PolymerIon-exchangeCapacity

n-propanolweight

fraction,%

WaterUptake,%

SaltPermeability,Ps(107cm2/s)

ChargeEfficiency,

%

SaltAbsorptionCapacity(SAC),

Mg/g1.0 50 36 0.79 80.8 10.01.5 50 101 3.46 87.8 10.22.0 50 203 4.17 88.7 11.52.0 10 122 1.54 77.6 8.12.0 20 51 0.47 84.1 9.02.0 30 144 2.95 90.1 9.12.0 40 NA NA 92.0 9.52.0 60 244 5.90 79.7 8.8

MCDIwithcommercialIEMs 21 0.21 87.6 12.0

(a)IEC1.0_50%n-propanol (b)IEC1.5_50%n-propanol (c)IEC2.0_50%n-propanol

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Figure S6. Additional TEM images obtained through longer staining. The figure

demonstrates the morphology of the polymer films when cast form the casting solvent

blend with (a) 10 wt % n-propanol, (b) 20 wt % n-propanol, (c) 30 wt % n-propanol, (d)

40 wt % n-propanol, (e) 50 wt % n-propanol, and (f) 60 wt % n-propanol. The black color

particles in figure “a,c,d,f” are the artifacts due to crystallization of the staining agent on

the membrane films.

(a)10%n-propanol (b)20%n-propanol (c)30%n-propanol

(e)50%n-propanol(d)40%n-propanol (f)60%n-propanol