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Tailoring the pore size of hypercrosslinked polymers†

Buyi Li, Ruini Gong, Yali Luo and Bien Tan*

Received 14th June 2011, Accepted 22nd August 2011

DOI: 10.1039/c1sm06113e

We report here a practical method to tailor the pore size of hypercrosslinked poly(divinylbenzene-co-

vinylbenzyl chloride) (HCP-DVB-VBC) by adjusting the DVB content in poly(divinylbenzene-co-

vinylbenzyl chloride) (DVB-VBC) precursors, and then hypercrosslinking these DVB-VBC precursors.

With the DVB content varying from 0–10%, the pore size of HCP-DVB-VBC decreases, the pore size

distribution becomes narrower and the micropore volume content increases from 6.82 to 61.90%.When

the DVB content is higher than 7%, the HCP-DVB-VBC changes to pure microporous organic

polymer.

Introduction

The porous materials with extraordinary high surface area have

attracted extensive attention these days due to their diverse

potential applications in separators,1 heterogeneous catalysts2,3

and gas storage.4–7 Various new methodologies are being

developed and older ones being improved to produce diverse

classes of porous material, including zeolites, activated carbons,

silica, and metal organic frameworks (MOFs), covalent organic

frameworks (COFs)8,9 etc.

Porous organic polymers10 exhibit the unique properties of

large surface areas, low skeleton density and high chemical

stabilities compared to other kinds of porous materials and are

thus gradually becoming an important and attractive class of

porous materials. Very recently, various synthetic strategies have

been reported to produce a variety of new porous organic

polymers, such as polymers of intrinsic microporosity (PIMs)

with dioxane units,5 microporous polymers, such as conjugated

microporous polymer (CMP),11,12 porous aromatic frameworks

(PAF)13 by cross-coupling reaction of aromatic compounds,

element–organic frameworks (EOF) via an organometallic

polymer synthesis route,14 knitting aromatic compound poly-

mers (KAPs) by external crosslinking,15 polymerization of tri-

merization of ethynyl groups16 or nitrile groups,17 and amide or

imide or imine formation.18–21 However, the transition metal

catalysts or noble metal catalysts used for the synthesis of CMPs,

PAFs and other porous organic polymers are rare and expensive

thus limiting the practical application of these synthetic strate-

gies. Although changing the rigid building block unit can adjust

College of Chemistry and Chemical Engineering, Huazhong University ofScience and Technology, Wuhan, 430074, China. E-mail: bien.tan@mail.hust.edu.cn; Fax: +86 27 87543632; Tel: +86 27 87558172

† Electronic supplementary information (ESI) available: The FE-SEMimage of fracture section of samples with 0%, 0.5%, 1%, 2%, 5% and10% DVB before and after hypercrosslinking reaction. See DOI:10.1039/c1sm06113e

10910 | Soft Matter, 2011, 7, 10910–10916

the pore size in the range of micropore to mesopore scale11 for

porous organic polymers mentioned above, it is hard to get

a uniformmicroporous structure, which restricts the applications

of porous organic polymers in molecular sieves, high-perfor-

mance liquid chromatography (HPLC) column packing mate-

rials, and selective catalysis etc.

Davankov resins, i.e., hypercrosslinked styrene-type polymers

(HCPs) synthesized via Friedel–Crafts reaction,22 were one of the

earliest porous organic polymers, which found their way to

industry by the end of 1990s.23 Since then various improved

HCPs have been used in broad applications. In addition to the

use of HCPs to adsorb and thus remove toxic organic24,25 and

inorganic26,27 contaminations in solution, they have been used to

remove toxic gases and as gas storage materials28 (hydrogen gas

adsorption).29 They have also been used as the stationary phase

in chromatography.30,31 The matrix of HCPs has also been used

to prepare nanocomposites and exhibit particular catalytic31 and

magnetic properties.32 Initially, HCPs have been mainly prepared

by hypercrosslinking of linear22 or lightly cross-linked gel-type

polystyrenes using external electrophiles to introduce the new

crosslinks.33,34 The resulting hyper-cross-linked polystyrene

materials possess very high microporosity and thus high surface

area. They also show interesting swelling properties, despite the

high degree of cross-linking. Moreover, the resins swell to similar

degrees in both good and poor solvents for polystyrene. Subse-

quently, poly(divinylbenzene-co-vinylbenzyl chloride) (DVB-

VBC) are proved as excellent precursors for the synthesis of

hypercrosslinked poly(divinylbenzene-co-vinylbenzyl chloride)

(HCP-DVB-VBC) where the –CH2–Cl substituent actually yields

an internal electrophile to form the basis of the crosslinks using

SnCl4 as catalyst.35 Sherrington and his co-workers have opti-

mized the synthesis conditions, including the ratios of different

vinylbenzyl chloride monomers,36 catalyst,37 and obtained the

HCP-DVB-VBCwith amaximum surface area up to 2000 m2 g�1.

Despite extensive work on the synthesis of microporous HCP-

DVB-VBC, the control over the pore size and pore distribution is

This journal is ª The Royal Society of Chemistry 2011

Scheme 1 Bulk polymerization of DVB-VBC precursor and hyper-

crosslinking reaction pathway.

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rarely reported. In our previous work,7 we reported that the

uniform nanoparticle morphology can help to create smaller and

more uniform pore structure due to similar hypercrosslinking

reaction circumstances for each nanoparticle, however, the

control over the pore size was very limited.

Here we report a simple method to produce HCP-DVB-VBC

with a fair control over the pore size and the pore size distribu-

tion, and to eventually generate a polymer with a uniform

microporous structure. The different pore structures of these

materials possess interesting and distinctive gas adsorption

Table 1 Composition, porosity of samples.g,h,i

No.DVBmol (%)

SBETa

m2 g�1

SL.b

m2 g�1

PVc

cm3 g�1

M.A.d

m2 g�1

MPVe

cm3 g�1

MPVf

%

1 0 1420 1930 1.29 232 0.088 6.822 0.5 1790 2480 1.86 75 0.0045 0.243 1 1860 2560 1.26 235 0.078 6.194 1.5 1890 2610 1.20 280 0.098 8.175 2 2060 2850 1.23 271 0.086 7.006 3 1920 2640 1.10 461 0.19 17.287 4 1840 2520 1.04 617 0.26 25.008 5 1760 2410 0.99 639 0.27 27.279 6 1520 2060 0.82 866 0.39 47.5610 7 1430 1930 0.77 813 0.37 48.0511 8 1370 1830 0.70 864 0.39 55.7112 10 1260 1680 0.63 859 0.39 61.90

a Surface area calculated from nitrogen adsorption isotherms at 77.3 Kusing BET equation. b Surface area calculated from nitrogenadsorption isotherms at 77.3 K using Langmuir equation. c Porevolume calculated from nitrogen isotherm at P/P0 ¼ 0.995, 77.3 K. d t-Plot micropore area. e t-Plot micropore volume. f micropore volume (t-Plot)/Pore volume (calculated from nitrogen isotherm at P/P0 ¼ 0.995,77.3 K) *100%. g N2 uptake determined volumetrically usinga Micromeritics ASAP 2020 M analyzer at 1 bar and 77.3 K. h H2

uptake determined volumetrically using a Micromeritics ASAP 2020 Manalyzer at 1.13 bar and 77.3 K. i CO2 uptake determinedvolumetrically using a Micromeritics ASAP 2020 M analyzer at 1.00bar and 273.15 K.

This journal is ª The Royal Society of Chemistry 2011

properties. In order to explore the essential method to tune the

pore size and to eliminate interferences of many factors by

traditional suspension polymerization, for example, residual

Fig. 1 A FE-SEM image of fracture section of samples with 0%, 0.5%,

1%, 2%, 5% and 10% DVB before (a, scale 200 nm) and after (b, scale

100 nm) hypercrosslinking reaction. (Original images are shown as

Fig. S1–S12†).

Soft Matter, 2011, 7, 10910–10916 | 10911

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stabilizer, polydisperse particle size and so on, we chose bulk

polymerization to synthesize a series of DVB-VBC precursors,

and then hypercrosslink them to produce HCP-DVB-VBC as

model materials.

Experiment

Materials

Vinylbenzyl chloride (VBC, Aldrich, 98% grade, 30 : 70 w/w

mixtures of p-VBC and m-VBC isomers), divinylbenzene (DVB,

Aldrich, 80% grade), 2,2-azobis-(isobutyronitrile) (AIBN,

Fisher) was recrystallized from methanol prior to drying under

Fig. 2 Nitrogen adsorption (solid circle) and desorption (open c

10912 | Soft Matter, 2011, 7, 10910–10916

reduced pressure. FeCl3 (anhydrous, analytical grade) was

obtained from National Medicines Corporation Ltd. of China.

Synthesis of HCP-DVB-VBC

The synthesis route was shown in Scheme 1.

(i) Synthesis of DVB-VBC precursor. The DVB-VBC precursor

was prepared by free radical bulk polymerization. The quantities

of DVB (0–10 mol % based on VBC) and VBC (4 g) are

summarized in Table 1 and AIBN was 0.5 wt% based on

monomers for each reaction. The mixture of DVB, VBC and

AIBN was heated at 60 �C for 12 h, followed by drying in

ircle) isotherms at 77.3 K of samples with 0% to 10% DVB.

This journal is ª The Royal Society of Chemistry 2011

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a vacuum oven at 60 �C for 24 h to remove unreacted co-

monomers.

(ii) Preparation of HCP-DVB-VBC. The DVB-VBC precursor

(2 g) was swollen in 1, 2 -dichloroethane (DCE, 40 ml) under N2

for 24 h. FeCl3 (2 g) was added to the solution and then heated at

80 �C for 18 h. The resulting HCP-DVB-VBC was filtered and

washed three times with ethyl ether and methanol, washed with

methanol in a Soxhlet for 24 h, and finally dried in vacuum oven

Fig. 3 Pore size distributions calculated using DFT methods (slit pore

models, differential pore volumes. pore width) of samples with 0% to 10%

DVB. (a) Pore size distribution in the range between 4–3000 �A, (b) Pore

size distribution in the range between 4–30 �A.

This journal is ª The Royal Society of Chemistry 2011

at 60 �C for 24 h. The final products are brown irregularly shaped

powder particles.

Characterization

Polymer surface areas, N2 adsorption isotherm (77.3 K), pore

size distributions, CO2 uptake volumetric analysis (1 bar, 273.15

K) and H2 uptake volumetric analysis (1.13 bar, 77.3 K) were

measured using a Micromeritics ASAP 2020 M surface area and

porosity analyzer. Before analysis, the samples were degassed at

110 �C for 8 h under vacuum (10�5 bar). Polymer morphologies

were investigated using a FEI Sirion 200 field emission scanning

electron microscope (FE-SEM). For FE-SEM analysis, DVB-

VBC precursor fragments or HCP-DVB-VBC powders were

mounted on aluminum studs using adhesive graphite tape and

sputter-coated with platinum before analysis.

Result and discussion

Morphology of DVB-VBC precursor and HCP-DVB-VBC

FE-SEM images of DVB-VBC precursors and HCP-DVB-VBC

are shown in Fig. 1. The fracture section of DVB-VBC precursor

with 0% DVB (Fig. 1)is very smooth and have no visible porous

structure. The fracture section of DVB-VBC precursor with 0.5%

and 1% DVB shows obvious coarse surface and possess non

uniform pores smaller than 200 nm. By increasing DVB contents,

the fracture section of DVB-VBC precursors, with 2%, 5% and

10% DVB, resulted in smooth surface with no obvious porous

structure. After hypercrosslinking reaction, the fracture section

of HCP-DVB-VBC with 0% DVB exhibited visible pores of less

than 50 nm; the fracture section of HCP-DVB-VBC with 0.5%

DVB shows visible pores of about several nanometres; the frac-

ture section of Davankove resins with 1% DVB possess quite

similar pore structure with the one produced with 0.5%DVB, but

the visible pore size is smaller; the fracture sections of HCP-

DVB-VBC with 2%, 5% and 10% DVB do not indicate visible

pore structure, and by increasing the DVB contents, the fracture

section became smoother, for the fracture section of HCP-DVB-

VBC with 10%, there is no obvious coarse surface even on 20 000

times amplification factor.

Surface area and pore size distribution

FE-SEM images can only show visible pore structure, but

micropores (less than 2 nm) are too small to be observed using

FE-SEM. Hence the nitrogen gas adsorption method was used to

calculate the surface area and the pore size distribution. The BET

surface area, Langmuir surface area, pore volume, t-Plot

micropore area, t-Plot micropore volume and micropore content

are summarized in Table 1. The DVB-VBC precursors have

a nominal surface area of �2 m2 g�1 while the surface area of

HCP-DVB-VBC increases sharply to a remarkably high value

after the hypercrosslinking reaction of DVB-VBC precursors,

which is consistent with previous reports.37 By increasing DVB

concentration, the surface area of HCP-DVB-VBC initially

increases and then decreases. The HCP-DVB-VBC with 2%DVB

has the highest surface area up to 2064 m2 g�1, and the data agree

well with the previous reports.37 By increasing the DVB contents

(when DVB concentration is less than 2%), the surface area

Soft Matter, 2011, 7, 10910–10916 | 10913

Table 2 Gas adsorption properties of samples

No.DVBmol (%)

N2 uptakea

mmol g�1 (wt %)H2 uptake

b

mmol g�1 (wt %)CO2 uptake

c

mmol g�1 (wt %)

1 0 37.14 (103.50) 6.00 (1.20) 2.26 (9.93)2 0.5 53.80 (150.62) 6.40 (1.28) 2.27 (10.01)3 1 36.38 (101.88) 6.95 (1.39) 2.27 (10.02)4 1.5 34.68 (97.10) 7.00 (1.40) 2.28 (10.05)5 2 35.64 (99.80) 7.20 (1.42) 2.29 (10.07)6 3 31.63 (88.57) 7.35 (1.47) 2.52 (11.09)7 4 30.06 (84.17) 7.40 (1.48) 2.57 (11.32)8 5 28.60 (80.09) 7.50 (1.50) 2.57 (11.32)9 6 23.67 (66.28) 7.25 (1.45) 2.61 (11.50)10 7 22.21 (62.18) 7.15 (1.43) 2.70 (11.89)11 8 20.10 (56.28) 7.15 (1.43) 2.76 (12.17)12 10 18.28 (51.20) 7.10 (1.42) 2.82 (12.41)

a N2 uptake determined volumetrically using aMicromeritics ASAP 2020M analyzer at 1 bar and 77.3 K. b H2 uptake determined volumetricallyusing a Micromeritics ASAP 2020 M analyzer at 1.13 bar and 77.3 K.c CO2 uptake determined volumetrically using a Micromeritics ASAP2020 M analyzer at 1.00 bar and 273.15 K.

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increases. Using 0.5% DVB, the surface area was increased from

1417 to 1790 m2 g�1. However, by increasing the DVB contents

(when DVB concentration is more than 2%), the –CH2Cl content

decreases, which results in a decrease in the surface area. The

nitrogen adsorption isotherms/desorption isotherms at 77.3 K

(Fig. 2) and pore size distribution analysis of HCP-DVB-VBC

Scheme 2 Sketch map of HCP-DVB-VBC with 0% DVB (a), precursor

of HCP-DVB-VBC with some DVB (less, (b); more, (c)).

10914 | Soft Matter, 2011, 7, 10910–10916

with various DVB contents were calculated using DFT methods

(slit pore models, Differential Pore Volume vs. Pore Width,

Fig. 3), which agree well with their pore structure shown in FE-

SEM images (Fig. 1). As shown in Fig. 2, the adsorption

isotherms of all samples show a steep nitrogen gas uptake at low

relative pressure (P/P0 < 0.001) thus reflecting abundant micro-

porous structure. Nitrogen adsorption and desorption isotherms

of HCP-DVB-VBC with 0% and 0.5% DVB have a clear

hysteresis loop, which indicated the mesoporous structure, and

exhibited a remarkable rise in the medium and high pressure

regions (P/P0 ¼ 0.8–1.0), which shows the presence of macro-

pores in the materials.38 The pore size distribution also shows the

presence of micropores, mesopores and macropores in the

materials simultaneously. By increasing the DVB contents (1–

6%), the hysteresis loop disappears gradually, which implies that

the mesoporous structure is diminishing and the mild rise in the

medium and high pressure regions (P/P0 ¼ 0.8–1.0) shows the

existence of a few macropores. The peaks beyond 2 nm of pore

size become weaker by increasing the DVB contents, indicating

again that by increasing DVB content, the meso- and macropores

are significantly reduced. When the DVB concentration is over

7%, the nitrogen adsorption and desorption isotherm line with

a very flat course in the intermediate section is a typical Type I

according to the IUPAC classification and there are no peaks in

meso- and macropore regions in the pore size distribution, an

indication of a sheer microporous materials.38 Besides the

disappearance of macro- and mesoporous structures, smaller

micropores are also obtained by increasing the DVB content as

the peaks obviously shift to a lower value, shown in the pore size

distribution at region below 2 nm. Table 2 summarizes a series of

quantitative pore properties. Apart from HCP-DVB-VBC with

0% DVB, by increasing the DVB content the total pore volume

decreases, but the micropore volume and micropore proportion

in total pore volume increases. All the above results indicate that

the increase of DVB content can effectively produce a more

uniform and narrower microporous structure.

There are several reasons to explain the variation in the surface

area and pore size distribution of these polymeric materials.

According to the previous reports,23 in order to form the cross-

bridge –CH2–, (i) the intermolecular cross-bridges emerge at the

very beginning with the same probability as the intramolecular

crosslinks; (ii) two phenyl rings belonging to two different chains

(or to distant segments of the same chain) of polymers react with

the cross-linking agent to form a cross-bridge; (iii) formation of

a second bridge between two neighboring rings of the same

chains (or segments) is improbable, since it would imply a closure

of a stressed cycle. It means in the neighbourhood of a bridge,

a phenyl ring would be more likely interact with phenyls of a

third chain (or of distant segments of the same chain). It is thus

a random process to form intermolecular cross-bridges in distant

segments of the same chain or intramolecular cross-bridges when

several macromolecular chains twist together coincidentally

under the above three pre-conditions. As shown in Scheme 2(a),

for the DVB-VBC precursor with 0% DVB, the loose and

disordered twisted macromolecular chains dissolve well in

solvent, the distance between two neighbouring chains (or two

space neighbours but distant segments of one chain, as shown in

Scheme 2(a) is random. It implies that every –CH2Cl group does

not possess neighbouring benzene ring satisfying these rules,

This journal is ª The Royal Society of Chemistry 2011

Table 3 Adsorption capacities of H2 or CO2 on various materials reported

Materials SBET m2 g�1 PV cm3 g�1 MPV cm3 g�1

H2 uptakea

mmol g�1 (wt %)CO2 uptake

b mmol g�1

(wt %)1 bar or 30 bar References

AC Norit UOK A 1195 0.65 0.47 8.35 (1.67) 39AC Norit SX 1 G 1176 0.83 0.40 8.35 (1.67) 39AC Norit SX plus 1051 0.79 0.35 7.35 (1.47) 39AC Norit SX 1G AIR 1030 0.68 0.36 7.63 (1.53) 39MCM-41 1017 1.04 0.00 2.90 (0.58) 39HCP-1 1646 1.26 0.66 1.7 (7.48); 13.3 (58.52) 40HCP-2 1684 1.47 0.64 1.7 (7.48); 12.6 (55.44) 40HCP-3 1531 1.44 0.60 1.6 (7.48); 11.6 (51.04) 40HCP-4 1642 1.74 0.59 1.6 (7.48); 10.6 (44.26) 40

a H2 uptake determined at 1 bar and 77 K quoted by references. b CO2 uptake determined at 1 bar or 30 bar and 298 K quoted by references.

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which results in random hypercrosslinking density and the

appearance of macropores in HCP-DVB-VBC, as shown in FE-

SEM images (Fig. 1) and pore size distribution graphs (Fig. 3).

For the DVB-VBC precursor containing DVB, it is almost fully

swollen in solvent and every chain lightly-crosslinked by DVB is

not so free to disperse in solvent, which reduces the distance

between them; for the lower crosslinked DVB-VBC precursor

(e.g., precursor with 0.5% and 1% DVB), the chains are fixed to

each other by DVB, but the chains are also very loose so that the

distance between two chains is not uniform everywhere, hence, it

still has quite similar a situation to the DVB-VBC precursor with

0% DVB in terms of formation of an uneven pore structure.

Besides, limited DVB can only crosslink a restricted number of

chains into a network, therefore, there are many tiny and non-

uniform pores on the polymer surface and its bulk, as shown in

FE-SEM images of the polymer with 0.5% and 1% DVB (Fig. 1).

The heterogeneous precursor texture remains after hyper-

crosslinking to some degree because it is too far to form the

cross-bridge between the tiny bulks. In other words, the hyper-

crosslinking reaction usually occurs in a compact polymer chains

region. For these two reasons, the HCP-DVB-VBC with lower

DVB content presents a heterogeneous pore structure, as shown

in FE-SEM images (Fig. 1) and pore size distribution graphs

(Fig. 3). The non-linear crosslinked precursor with higher DVB

content presents a more uniform texture, as shown in FE-SEM

images (Fig. 1), which favoured a uniform pore structure after

the hypercrosslinking reaction. On the other hand, the precursor

with a higher crosslinking degree possess a more rigid network,

and the distance between each chain tended to be more identical

at every location (comparing Schemes 2(b) and (c)), which means

the hypercrosslinking degree will be more uniform throughout

the polymer. The fracture section of HCP-DVB-VBC with 2% to

10% DVB (Fig. 1) thus represents smoother, narrower and more

uniform pore size distribution (Fig. 3).

Gas adsorption properties

As shown in the Table 2, nitrogen gas, hydrogen gas and carbon

dioxide gas adsorption properties are different for different

samples. HCP-DVB-VBC with 2% DVB possesses the best

nitrogen gas adsorption properties (53.80 mmol g�1, 150.62 wt

%), HCP-DVB-VBC with 5% DVB shows the greatest hydrogen

gas adsorption (7.50 mmol g�1, 1.50 wt%), and HCP-DVB-VBC

with 10% DVB adsorbs the most carbon dioxide gas (2.82 mmol

This journal is ª The Royal Society of Chemistry 2011

g�1, 12.41 wt%). There are many factors affecting the gas

adsorption properties, such as the nature of adsorbate and

chemical structure, surface area, pore morphology, pore size and

pore size distribution of the adsorbent material. The materials

studied in this work should have, in principle, the quite similar

chemical structure and pore morphology; therefore, if they show

different adsorption properties for the same gas adsorbate, the

most crucial factors should be the surface area (calculated by

nitrogen gas adsorption at 77.3 K) and pore size and pore size

distribution. For HCP-DVB-VBC with similar surface areas, the

hydrogen gas and carbon dioxide gas adsorption are higher for

those with a smaller micropore size and higher microporous

volume, for example, the HCP-DVB-VBC with 0.5% DVB (1790

m2 g�1; H2 uptake, 1.28 wt%; CO2 uptake, 10.01 wt%) and HCP-

DVB-VBC with 5% DVB (1760 m2 g�1; H2 uptake, 1.50 wt%;

CO2 uptake, 11.32 wt%), the HCP-DVB-VBC with 1% DVB

(1858 m2 g�1; H2 uptake, 1.39 wt%; CO2 uptake, 10.02 wt%) and

HCP-DVB-VBC with 4% DVB (1841 m2 g�1; H2 uptake, 1.48 wt

%; CO2 uptake, 11.32 wt%). That smaller pore size and higher

microporous volume facilitate gas adsorption is consistent with

literature reports on other classes of porous materials. Nijkamp

and co-workers have systemically researched zeolites and

activated carbons and found out for analogs, the higher the

micropore volume is, the higher the H2 adsorption is.39 Mart�ın

and co-workers have researched the hypercrosslinked polymers

based on co-polycondensation of p-dichloroxylene (p-DCX) and

4,4-bis(chloromethyl)-1,10-biphenyl (BCMBP) and found out

that CO2 uptakes at atmospheric pressure and ambient temper-

ature seem to correlate better with narrow micropore volumes.40

The gas uptake data of materials mentioned above have been

summarized in Table 3.

Conclusion

In this report, we have demonstrated that the pore structure of

HCP-DVB-VBC can be adjusted from macropore to micropore

scale by changing the DVB contents. When the DVB concen-

tration is up to 7%, sheer microporous structure can be obtained.

The mechanism of effect of DVB content in controlling the pore

structure is proposed. The experimental data indicate that the

smaller micropore size and higher microporous volume favors

the H2 and CO2 gas adsorption. Compared to other costly

porous organic materials, these cost-efficient polymers (HCP-

DVB-VBC) with a tunable pore structure would have broad

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feasible applications as molecular sieves, chromatographic

column packing materials, selective catalysis etc.

Acknowledgements

We thank Analysis and Testing Center, Huazhong University of

Science and Technology for characterization assistance. This

work was financially supported by the program for New Century

Excellent Talents in University (NCET-10-0389), Shanghai

Tongji Gao Tingyao Environmental Science & Technology

Development Foundation (STGEF) and National Natural

Science Foundation of China (No. 50973037 and No. 51173058).

References

1 N. B. McKeown and P. M. Budd, Chem. Soc. Rev., 2006, 35, 675.2 X. Du, Y. Sun, B. Tan, Q. Teng, X. Yao, C. Su and W. Wang, Chem.Commun., 2010, 46, 970.

3 D. Dang, P. Wu, C. He, Z. Xie and C. Duan, J. Am. Chem. Soc., 2010,132, 14321.

4 H. Furukawa and O. M. Yaghi, J. Am. Chem. Soc., 2009, 131, 8875.5 N. B. McKeown, B. Gahnem, K. J. Msayib, P. M. Budd,C. E. Tattershall, K. Mahmood, S. Tan, D. Book, H. W. Langmiand A. Walton, Angew. Chem., 2006, 118, 1836.

6 C. D. Wood, B. Tan, A. Trewin, F. Su, M. J. Rosseinsky,D. Bradshaw, Y. Sun, L. Zhou and A. I. Cooper, Adv. Mater.,2008, 20, 1916.

7 B. Li, X. Huang, L. Liang and B. Tan, J. Mater. Chem., 2010, 20,7444.

8 A. P. Cote, A. I. Benin, N. W. Ockwig, M. O’Keeffe, A. J. Matzgerand O. M. Yaghi, Science, 2005, 310, 1166.

9 H. M. El-Kaderi, J. R. Hunt, J. L. Mendoza-Cortes, A. P. Cote,R. E. Taylor, M. O’Keeffe and O. M. Yaghi, Science, 2007, 316, 268.

10 J.-X. Jiang and A. Cooper, in Functional Metal–Organic Frameworks:Gas Storage, Separation and Catalysis, ed. M. Schr€oder, Springer,Berlin/Heidelberg, 2010, p. 1.

11 J. X. Jiang, F. Su, A. Trewin, C. D. Wood, H. Niu, J. T. A. Jones,Y. Z. Khimyak and A. I. Cooper, J. Am. Chem. Soc., 2008, 130, 7710.

12 J. Schmidt, M. Werner and A. Thomas, Macromolecules, 2009, 42,4426.

13 T. Ben, H. Ren, S. Ma, D. Cao, J. Lan, X. Jing, W. Wang, J. Xu,F. Deng, J. Simmons, S. Qiu and G. Zhu, Angew. Chem., Int. Ed.,2009, 48, 9457.

14 M. Rose, W. Bohlmann, M. Sabo and S. Kaskel, Chem. Commun.,2008, 2462.

15 B. Li, R. Gong, W. Wang, X. Huang, W. Zhang, H. Li, C. Hu andB. Tan, Macromolecules, 2011, 44, 2410.

10916 | Soft Matter, 2011, 7, 10910–10916

16 S. W. Yuan, B. Dorney, D. White, S. Kirklin, P. Zapol, L. P. Yu andD. J. Liu, Chem. Commun., 2010, 46, 4547.

17 P. Kuhn, M. Antonietti and A. Thomas, Angew. Chem., Int. Ed.,2008, 47, 3450.

18 J. Weber, M. Antonietti and A. Thomas, Macromolecules, 2008, 41,2880.

19 P. Pandey, A. P. Katsoulidis, I. Eryazici, Y. Wu, M. G. Kanatzidisand S. T. Nguyen, Chem. Mater., 2010, 22, 4974.

20 F. J. Uribe-Romo, J. R. Hunt, H. Furukawa, C. Kl€ock, M. O’Keeffeand O. M. Yaghi, J. Am. Chem. Soc., 2009, 131, 4570.

21 Y. Luo, B. Li, L. Liang and B. Tan, Chem. Commun., 2011, 47, 7704.22 V. A. Davankov, S. V. Rogozhin and M. P. Tsyurupa, US 3729457,

1971.23 M. P. Tsyurupa and V. A. Davankov, React. Funct. Polym., 2006, 66,

768.24 C.-F. Chang, C.-Y. Chang, K.-E. Hsu, S.-C. Lee and W. H€oll, J.

Hazard. Mater., 2008, 155, 295.25 V. Davankov, L. Pavlova, M. Tsyurupa, J. Brady, M. Balsamo and

E. Yousha, J. Chromatogr., Biomed. Appl., 2000, 739, 73.26 M. P. Tsyurupa, O. G. Tarabaeva, A. V. Pastukhov and

V. A. Davankov, Int. J. Polym. Mater., 2003, 52, 403.27 B. Li, F. Su, H.-K. Luo, L. Liang and B. Tan, Microporous

Mesoporous Mater., 2011, 138, 207.28 C. Long, Q. Li, Y. Li, Y. Liu, A. Li and Q. Zhang, Chem. Eng. J.,

2010, 160, 723.29 J. Y. Lee, C. D. Wood, D. Bradshaw, M. J. Rosseinsky and

A. I. Cooper, Chem. Commun., 2006, 2670.30 V. Davankov, M. Tsyurupa,M. Ilyin and L. Pavlova, J. Chromatogr.,

A, 2002, 965, 65.31 C. S. Sychov, M. M. Ilyin, V. A. Davankov and K. O. Sochilina, J.

Chromatogr., 2004, 1030, 17.32 S. N. Sidorov, L. M. Bronstein, V. A. Davankov, M. P. Tsyurupa,

S. P. Solodovnikov, P. M. Valetsky, E. A. Wilder andR. J. Spontak, Chem. Mater., 1999, 11, 3210.

33 V. A. Davankov and M. P. Tsyurupa, React. Polym., 1990, 13, 27.34 M. P. Tsyurupa and V. A. Davankov, React. Funct. Polym., 2002, 53,

193.35 P. Veverka and K. Jerabek, React. Funct. Polym., 1999, 41, 21.36 N. Fontanals, J. Cortes, M. Galia, R. M. Marce, P. A. G. Cormack,

F. Borrull and D. C. Sherrington, J. Polym. Sci., Part A: Polym.Chem., 2005, 43, 1718.

37 J. H. Ahn, J. E. Jang, C. G. Oh, S. K. Ihm, J. Cortez andD. C. Sherrington, Macromolecules, 2006, 39, 627.

38 K. S. W. Sing, D. H. Everett, R. A. W. Haul, L. Moscou,R. A. Pierotti, J. Rouquerol and T. Siemieniewska, Pure Appl.Chem., 1985, 57, 603.

39 M. G. Nijkamp, J. Raaymakers, A. J. van Dillen and K. P. de Jong,Appl. Phys. A: Mater. Sci. Process., 2001, 72, 619.

40 C. F. Mart�ın, E. St€ockel, R. Clowes, D. J. Adams, A. I. Cooper,J. J. Pis, F. Rubiera and C. Pevida, J. Mater. Chem., 2011, 21, 5475.

This journal is ª The Royal Society of Chemistry 2011