Phosphonated homopolymers and copolymers via ring opening metathesis polymerization: Tg tuning, flame resistance, and photolithography

Article abstract of DOI:10.1002/pola.27990

Phosphonated and epoxy-containing norbornene based monomers were prepared by Diels-Alder reaction. They were then combined with three other commercial cyclic unsaturated monomers to synthesize phosphonated homopolymers and copolymers via ring opening metathesis polymerization (ROMP) using second-generation Grubbs catalyst. Glass transitions of these polymers were tunable in a broad range from -14 to 91 °C by varying the flexibility of comonomer. Interestingly, copolymerization with cyclopentene inhibited the crystallization of polycyclopentene, and instead, led to a copolymer with two T_gs. Paradoxically, results from thermogravimetric analysis (TGA) were not consistent with the followed flame-retarding experiment, implying that the early weight loss from phosphonated moieties did not deleteriously affect the flame-resistant property which actually depended more on the percentage of char residual after thermal degradation. In application studies, the norbornene derivative phosphonated polymer was tested for the first time as flame retarding material, and showed significant self-extinguishing ability. In a second study, photolithography was also successfully performed via thiol-ene "click" chemistry, which allowed the phosphonated polymer a promising negative photoresist.

Full text of DOI:10.1002/pola.27990

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
Phosphonated Homopolymers and Copolymers via Ring Opening
Metathesis Polymerization: Tg Tuning, Flame Resistance, and
Photolithography
Xiaojuan Zhang,1 Qian Zhang,1 Chao Xie,2 Aiting Gao,3 Zheng Chang,1
Jung Kwon Oh,4 Peng Yang,3 Pengfei Li5
1Department of Applied Chemistry, Xi’an University of Technology, No. 5 South Jinhua Road, Xi’an, Shaanxi, 710048,
People’s Republic of China
2Department of Oral Implantology, State Key Laboratory of Military Stomatology, School of Stomatology, the Fourth Military
Medical University, No. 169 West Changle Road, Xi’an, Shaanxi, 710032, People’s Republic of China
3Key Laboratory of Applied Surface and Colloids Chemistry of Ministry of Education, School of Chemistry and Chemical
Engineering, Shaanxi Normal University, No. 199 Chang’an South Road, Xi’an, Shaanxi, 710119, People’s Republic of China
4Department of Chemistry and Biochemistry and Center for Nanoscience Research (CENR), Concordia University, 7141
Sherbrooke St. West, Montreal, Quebec, H4B 1R6, Canada
5Frontier Institute of Science and Technology (FIST), Xi’an Jiaotong University, No. 99 Yanxiang Road, Xi’an, Shaanxi, 710054,
People’s Republic of China
Correspondence to: Q. Zhang (E-mail: qzh@xaut.edu.cn) or P. Li (E-mail: lipengfei@mail.xjtu.edu.cn)
Received 11 October 2015; accepted 4 November 2015; published online 2 December 2015
DOI: 10.1002/pola.27990
ABSTRACT: Phosphonated and epoxy-containing norbornene
based monomers were prepared by Diels–Alder reaction. They
were then combined with three other commercial cyclic unsat-
urated monomers to synthesize phosphonated homopolymers
and copolymers via ring opening metathesis polymerization
(ROMP) using second-generation Grubbs catalyst. Glass transi-
tions of these polymers were tunable in a broad range from
214 to 91 8C by varying the flexibility of comonomer. Interest-
ingly, copolymerization with cyclopentene inhibited the crystal-
lization of polycyclopentene, and instead, led to a copolymer
with two Tgs. Paradoxically, results from thermogravimetric
analysis (TGA) were not consistent with the followed flame-
retarding experiment, implying that the early weight loss from
phosphonated moieties did not deleteriously affect the flame-
resistant property which actually depended more on the per-
centage of char residual after thermal degradation. In applica-
tion studies, the norbornene derivative phosphonated polymer
was tested for the first time as flame retarding material, and
showed significant self-extinguishing ability. In a second study,
photolithography was also successfully performed via thiol-ene
“click” chemistry, which allowed the phosphonated polymer a
C
V
promising negative photoresist.
2015 Wiley Periodicals, Inc.
J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1396–1408
KEYWORDS: flame resistance; photolithography; norbornene;
phosphonate; ROMP
Phosphate, phosphonate, and phosphinate were the most
studied in literatures,7 other examples can be phosphazene
derivatives.2,12 Free radical polymerization may be the most
conventional method in obtaining PCPs. Since Kosolapoff
observed polymerizability of vinylphosphonate, homopoly-
mers and copolymers were prepared in free radical way till
recently.13–20 To achieve more control on the polydispersity
and chemical structure, anionic polymerization,21,22 and con-
trolled free radical polymerization23,24 were successfully
developed. Rare-earth metal mediated polymerization has
recently be employed to obtain high molecular weight poly-
vinylphosphonate,13,25–27 which presented exciting opportu-
nities to obtain new macromolecular architectures despite of
INTRODUCTION Phosphorus containing polymers (PCPs) have
played versatile roles in shaping the world. Biologically, poly-
phosphate backbone upholds nucleic acids and insures inheri-
tance of human beings.1 In industry, PCPs are very promising
as halogen-free flame retardants.2–6 They are also very good
adhesives to bind metals due to potentially strong complexa-
tion abilities, which also found applications in dental and bone
tissue engineering.7–9 In the development of highly efficient
proton-conducting fuel-cell membranes, PCPs can compete
with sulfonic acid materials for highly chemical and thermal
stabilities.10–12 The great interest in these fields has stimu-
lated the originality in exploring new chemical structures of
PCPs, endeavors were made in this aim in the recent years.
Additional Supporting Information may be found in the online version of this article.
C
V
2015 Wiley Periodicals, Inc.
1396
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408

JOURNAL OF
POLYMER SCIENCE
WWW.POLYMERCHEMISTRY.ORG
ARTICLE
SCHEME 1 Monomers including some synthetic routes in the research.
a few limitations and the methodology is still under investiga-
tion.28 Among the synthetic techniques, ring opening metathe-
sis polymerization (ROMP) has seen an increasing interest in
the synthesis of PCPs since 200928,29 for some reasons: (1)
novel norbornene-based structure (phosphorous on side
chain)28 and some unsaturate linear structure (phosphorous
on backbone)8,30 can be obtained; (2) olefin methathesis cata-
lysts are highly tolerant of functional groups and reaction con-
ditions are milder (even in ionic liquids)31 compared to
anionic and controlled radical polymerizations;28 (3) living
features and controllability are very good especially when the
third generation Grubbs catalyst is used.8,28,30
thiol-ene click chemistry,35 the current contribution is to verify
this point using selected PCPs synthesized.
The monomers used are shown in Scheme 1. Monomer 1 and 2
were synthesized via Diels–Alder addition using either diethyl
vinylphosphonate or glycidyl methacrylate with cylcopenta-
diene. Monomer 1 is a phosphonated component, 2 is epoxy-
containing and showing increasing interest in the preparation
of advanced epoxy curing resins.33 Besides, the recent devel-
oped thiol-epoxy “click” chemistry by Khan and coll. is expected
to be a very powerful tool for the postmodification of this
monomer and its polymer, and would be very promising in the
followed applications.36–39 Monomers 3 to 5 were from com-
mercial sources. Monomer 3 has an anhydride moiety which
can be transformed to carboxylic acid by hydrolysis and has
general interest in applications.28,40 Monomer 4 and 5 are less
bulky, and were used to gain more flexibility in the chemical
structures (note: monomer 5 incorporates linear structure with
double bond, so should be more flexible than monomer 4).
The current contribution targets at learning the thermal proper-
ties of PCPs via ROMP method on the homopolymer and copoly-
mer of norbornene based polymers because these information
are very important in applications,32 however, not paid much
attention till now [except in Ref. (28)], especially when flexibil-
ity is tuned by adjusting the chemical structures of macromolec-
ular backbones. Besides, an epoxy-containing norbornene
monomer with rising potentials as a new crosslinker in resin
industry was also used in this study.33,34 A second aim of this
contribution is to test the flame retardance and photo resistance
of PCPs for the promising industrial applications. Although
phosphazene-based polymers have showed significant flame-
retarding property in halogen-free epoxy thermosetting sys-
tems,2 PCPs from ROMP have not been reported for the same
use so far. In this contribution, it is for the first time
norbornene-based PCP homopolymer was tested for this pur-
pose. On the other hand, polymers used as photoresist in lithog-
raphy prepared via ROMP have proved very effective through
Polymers studied in the research were classified into homo-
polymers and copolymers, shown in Scheme 2. Statistical
copolymers were prepared from equimolar monomers except
CP3 where less monomer 3 was used due to poor solubility
of resulting polymers.
EXPERIMENTAL
Materials and Characterization
Materials were obtained from commercial sources and were
used without further purification unless otherwise specified.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408
1397

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
SCHEME 2 Synthetic routes of polymers in the research.
Triethyl phosphate (98%), methanol (AR), dimethyl sulfoxide
(AR), benzene (GR), xylene (AR), and triethylamine (AR)
were purchased from Sinopharm Chemical Reagent. 1,2-
Dibromoethane (99%), dicyclopentadiene (97%, endo form,
containing 100–200 ppm TBC as stabilizer), cyclopentene
(96%), ethyl vinyl ether (98%, containing 0.1% KOH as sta-
bilizer), bromotrimethylsilane (98%, containing Cu as stabi-
lizer), cis25-norbornene-endo-2,3-dicarboxylic anhydride
(99%), and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide
(Lucirin TPO, 97%) were from Aladdin Corp. Glycidyl meth-
acrylate (GMA, 96%, containing 100 ppm MEHQ as inhibitor)
and pentaerythritol tetra(3-mercaptopropionate) (PETMP,
90.0%) were from J&K Scientific. The Grubbs second genera-
tion catalyst, 1,3-bis(2,4,6-trimethylphenyl)22-(imidazolidi-
nylidene)(dichlorophenylmethylene)(tricyclohexylphosphi-
ne)ruthenium (97%) was from Beijing HWRK Chem.
Tetrahydrofuran (THF) and dichloromethane (DCM) were all
HPLC grade from Oceanpak and the DCM was degassed
before use. HPLC acetonitrile was from Kermel inc. 2-
Norbornene (>99.00%) was from TCI. The purification of
triethylamine was according to reference.41
are tabulated in the following order: chemical shift (ppm);
multiplicity (s, singlet; d, doublet; t, triplet; m, complex mul-
tiplet); number of protons.
Relative molecular weight (MW) and polydispersity index
(PDI) were determined by gel permeation chromatography
(GPC, Malvern Viscotek 270MAX) from Malvern Instruments.
It was equipped with a VE 3580 refractive index (RI) detector.
Two PolyAnalytik columns (LT3000L and LT6000L) were
used with THF as eluent at 35 8C at a flow rate of 1 mL/min.
The FTIR spectra of the samples were recorded on a Shi-
madzu Prestige-21 ATR spectrometer equipped with ZnSe
crystal by single reflection in the range 4000–650 cm21
.
Differential scanning calorimetry (DSC) was used to deter-
mine the temperature and enthalpy of transitions of the
polymers protected in high purity N2 using Mettler Toledo
DSC 1. Samples were sealed in aluminum pans (40 lL) and
scanned at a heating rate of 20 8C/min and cooling rate of
10 8C/min.
1H-NMR spectra were recorded using a Bruker Advance III
400 MHz spectrometer equipped with autosampler. The
CDCl3 singlet at 7.26 ppm and DMSO-d6 quintet at 2.5 ppm
were selected as the reference standard. Spectral features
Thermogravimetric analysis (TGA) was conducted using a Q50
thermogravimetric analyzer from TA Instruments. Samples
were placed in platinum crucibles scanned from 100 to 600 8C
under N2 atmosphere at a heating rate of 20 8C/min.
1398
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408

JOURNAL OF
POLYMER SCIENCE
WWW.POLYMERCHEMISTRY.ORG
ARTICLE
Monomer Synthesis
1H), 6.03 (m, 1H), 4.34 (m, 1H), 3.83 (m, 1H), 3.16 (m, 1H),
2.83 (m, 1H), 2.64 (m, 3H), 1.90 (dd, 1H), 1.55 (d, 2H), 1.42–
1.34 (m, 1H). ELEM. ANAL. Calcd. for C12H16O3: C, 69.21%; H,
7.74%; C/H, 8.942. Found: C, 70.23%; H, 7.69%; C/H, 9.137.
Synthesis of Diethyl-5-norbornen-2-ylphosphonate (NBDEP, 1)
First Step: Synthesis of Diethyl (b-Bromoethyl)
Phosphonate
Arbuzov reaction was made in this step based on reference
procedures.42 A round-bottom flask equipped with a reflux con-
denser was charged with 1,2-dibromoethane (5.515 mL, 64.00
mmol, 4.00 eq.) and triethylphosphite (2.716 mL, 16.00 mmol,
1.00 eq.). The mixture was then heated at 150–160 8C and
stirred for 13 h. The product was finally obtained as colorless
oil by vacuum distillation (2.651 g, 68%). H NMR (400 MHz,
CDCl3) d: 4.12 (m, 4H), 3.53 (m, 2H), 2.42–2.33 (m, 2H), 1.33
(t, 6 H).
Synthesis of Homopolymers HP1-5
Monomer 1–5 was homopolymerized, respectively, via ROMP
in the presence of second-generation Grubbs catalyst. In a
typical polymerization, a vial was charged with monomer
and a magnetic bar with the protection of argon. Then dry
degassed DCM was added to the vial to obtain a 0.1M solu-
tion. Catalyst as a stock solution in DCM (0.5 mol% with
respect to the monomer) was injected into the vial. The mix-
ture was left to react at room temperature for 6.5 h. When
reaction finished, ethyl vinyl ether (5 eq. to the monomer)
was added to quench the reaction. The homopolymer HP1
and 3 were purified by precipitation in ethyl ether and ace-
tone respectively, HP2, 4 and 5 were precipitated in metha-
nol. The products were dried in vacuum for 24 h. HP1: 1H
NMR (400 MHz, CDCl3) d: 5.74–5.62 (b), 5.40–5.26 (b), 4.04
(b), 3.19 (b), 2.81 (b), 2.35 (b), 2.04 (b), 1.91 (b), 1.73 (b),
1.28 (b). HP2: 1H NMR (400 MHz, CDCl3) d: 5.37–5.33 (b),
5.21 (b), 4.41 (b), 3.92 (b), 3.32–3.20 (b), 2.96 (b), 2.84 (b),
2.65 (b), 2.43 (b), 2.04 (b), 1.90 (b), 1.68 (b), 1.58 (b), 1.26–
1.08 (b). HP3: 1H NMR (400 MHz, DMSO-d6) d: 5.60 (b),
1
Second Step: Synthesis of Diethyl Vinylphophonate
(DEVP)
The mixture of diethyl (b-bromoethyl)phosphonate (2.651 g,
10.82 mmol, 1.00 eq.), triethylamine (2.190 mL, 15.15 mmol,
1.40 eq.), and benzene (4.130 mL, 46.53 mmol, 4.30 eq.) was
refluxed for 1 h. Then, the triethylamine hydrobromide was
filtered off and benzene was removed in reduced pressure.
The residue was further purified under reduced pressure to
1
obtain pure product as colorless oil (1.610 g, 91%). H NMR
(400 MHz, CDCl3) d: 5.70 (m, 1H), 5.11 (m, 2H), 4.01 (m,
4H), 2.50 (dd, 2 H), 1.22 (m, 6H).
1
5.43 (b), 3.54 (b), 2.99 (b), 1.78 (b), 1.27 (b). HP4: H NMR
Third Step: Synthesis of Monomer 1 (NBDEP)
(400 MHz, CDCl3) d: 5.34 (b), 5.21 (b), 2.79 (b), 2.43 (b),
1.80 (b), 1.56 (b), 1.35 (b), 1.04 (b). HP5: 1H NMR (400
MHz, CDCl3) d: 5.38 (b), 1.98 (b), 1.39 (b).
Diethyl Vinylphophonate (5.225 mL, 34.00 mmol, 1.00 eq.)
and freshly pyrolyzed cyclopentadiene (14.05 mL, 170.0
mmol, 5.00 eq.) were added to a round-bottom flask equipped
with a condenser. 2,6-Di-tert-butyl-4-methylphenol (119.9 mg,
0.5440 mmol, 0.0160 eq.) was added and the mixture was
refluxed for 14 h at 160–165 8C. At the end, the reaction mix-
ture was cooled and concentrated under reduced pressure
and purified by column chromatography (petroleum ether/
ethyl acetate5 7:3 v/v) to yield a yellowish oil (4.422 g,
56%). Endo: 1H NMR (400 MHz, CDCl3) d: 6.14 (S, 1H), 6.07
(S, 1H), 4.05 (m, 4H), 3.16 (S, 1H), 2.94 (S, 1 H), 2.00 (m, 1H),
1.44 (t, 1H), 1.33–1.25 (m, 8H), 1.19 (d, 1H). Exo: 1H NMR
(400 MHz, CDCl3) d: 6.14 (S, 1H), 6.07 (S, 1H), 4.05 (m, 4H),
3.16 (S, 1H), 2.94 (S, 1 H), 2.30 (m, 1H), 1.44 (t, 1H),
1.33–1.25 (m, 8H), 1.19 (d, 1H). ELEM. ANAL. Calcd. for
C11H19O3P: C, 57.38%; H, 8.32%; C/H, 6.897. Found: C,
56.50%; H, 8.32%; C/H, 6.795.
Synthesis of Statistical Copolymers CP2-5
To prepare CP2 typically, a flask was charged with 1
(252.4 mg, 1.10 mmol), 2 (228.1 mg, 1.10 mmol), DCM
(0.725 mL), and stirred with a magnetic bar in nitrogen flow.
Then, the second-generation Grubbs catalyst (9.490 mg, 11.2
mmol in 0.500 mL DCM) was injected into the flask to start
the reaction. The reaction was allowed to proceed at room
temperature for 10 h. The polymerization was quenched by
addition of excess of ethyl vinyl ether. The resulting polymer
was isolated by precipitation in hexane. Similarly,
1
(275.3 mg, 1.20 mmol), 3 (28.05 mg, 0.170 mmol), DCM
(0.700 mL), and catalyst (5.220 mg, 0.45 mol % relative to
the total of monomers) were used. The mixture was stirred
for 13 h at room temperature and then precipitated in ace-
tone/diethyl ether (1:9) to obtain CP3. To prepare CP4, 1
(275.3 mg, 1.20 mmol), 4 (112.6 mg, 1.20 mmol), DCM
(0.995 mL), and catalyst (12.49 mg, 0.60 mol % relative to
total monomers) were used. The polymer was isolated by
precipitation in hexane/diethyl ether (1:1) after being stirred
for 10 h at room temperature. For the synthesis of CP5, the
system with 1 (293.7 mg, 1.30 mmol), 5 (86.89 mg, 1.30
mmol), DCM (0.980 mL), and catalyst (13.13 mg, 0.60 mol %
relative to total monomers) was stirred for 11 h. The poly-
mer was isolated by precipitation in hexane/diethyl ether
(1:1). CP2: 1H NMR (400 MHz, CDCl3) d: 5.75–5.64 (b),
5.38–5.21 (b), 4.42 (b), 4.03 (b), 3.91 (b), 3.21 (b), 3.13–
2.83 (b), 2.64 (b), 2.37 (b), 2.20–1.65 (b), 1.38–1.07 (b),
0.88 (b). CP3: 1H NMR (400 MHz, CDCl3) d: 5.76–5.62 (b),
Synthesis of 5-Methylbicyclo[2.2.1]hept-2-ene-5-Carboxylic
Acid Glycidyl Ester (NBMGE, 2)
A round-bottom flask was charged with fresh cyclopenta-
diene (5.961 g, 90.18 mmol, 3.00 eq.) by pyrolysis of its
dimer, GMA (4.273 g, 30.06 mmol, 1.00 eq.), and 7.420 mL
xylene, then held at 140 8C for 10 h. The reaction mixture
was concentrated under reduced pressure and purified by
column chromatography using petroleum ether as the eluent
to get the pure product as a colorless oil (2.766 g, 44%).
Endo: 1H NMR (400 MHz, CDCl3) d: 6.19 (m, 1H), 6.05 (m,
1H), 4.43 (dd, 1H), 3.94 (m, 1H), 3.20 (m, 1H), 3.03 (s, 1H),
2.83 (m, 3H), 2.43 (dd, 1H), 1.42–1.34 (m, 2H), 1.11 (s, 3H),
0.86 (dd, 1H). Exo: 1H NMR (400 MHz, CDCl3) d: 6.11 (m,
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408
1399

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
SCHEME 3 Schematic process for negative lithography. [Color figure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
5.39–5.26 (b), 4.04 (b), 3.19 (b), 2.80 (b), 2.35 (b), 2.18–1.67
(b), 1.34–1.20 (b). CP4: 1H NMR (400 MHz, CDCl3) d: 5.75–
5.60 (b), 5.33–5.20 (b), 4.04 (b), 3.18 (b), 2.78 (b), 2.42 (b),
2.16–1.71 (b), 1.37–1.24 (b), 1.01 (b), 0.88 (b). CP5: H NMR
(400 MHz, CDCl3) d: 5.67 (b), 5.38 (b), 4.03 (b), 3.17 (b), 2.82
Flame-Resistant Experiment
Combustion experiments were carried out similar to UL-94
vertical burning experiments. A folded piece of print paper
(140.0 3 13.00 3 0.090 mm, A4, 70 g/m2) was used as the
testing substrate. Then, THF solution of polymer (100 mg/
mL) was used to apply a coating on the surface of the print
paper followed by drying with heat blower and kept at room
temperature for 18 h before use. The sample was ignited
using a butane gas lighter 5 mm underneath. The combus-
tion process was recorded with a digital camera. A blank
without polymer coatings was also tested in parallel.
1
(b), 2.37 (b), 1.96 (b), 1.70 (b), 1.40–1.28 (b).
Hydrolysis of PCPs
Bromotrimethylsilane (0.3950 mL, 2.990 mmol, 8.00 eq. to
the phosphonate ester group) was added dropwise to a solu-
tion of HP1 (86.00 mg, 0.3740 mmol) in dry DCM (0.955 mL)
in nitrogen flow. The reaction mixture was stirred for 24 h at
room temperature. After removing excess bromotrimethylsi-
lane under reduced pressure, methanol (1.515 mL) was added
to the mixture and stirred for 24 h at room temperature, and
then rotovaped to eliminate solvent and other volatile mole-
cules to obtain the corresponding phosphonic acid functional-
ized polymers. Copolymers (CP4 and CP5) were also
hydrolyzed using the procedure similarly.
Photolithography
Preparation of the Polymer Thin Film
The substrates of glass slide (1 mm in thickness) and silicon
wafer ([110] crystal plane, 0.43 mm in thickness) were
cleaned with piranha acid (H2SO4/H2O2 5 70/30 v/v) for 30
min at 80 8C (caution: Piranha acid reacts violently with
organic materials, so must be handled with great care). And
then they were washed with excess of deionized water, etha-
nol, and acetone for 15 min in sonicator. The cleaned silicon
wafers were precoated 5 nm Cr adhesion layer and then
45 nm thick gold layer and cleaned in plasma cleaner (PDC-
32G, Harrick) for 3 min. Solutions of polymer HP1 and CP4
(50 mg/mL) containing Lucirin TPO (10 wt % related to the
polymer) as photoinitiator and PETMP (vSH/C5C 5 4:1 for glass
slide, 6:1 for silicon wafer coated by gold) as crosslinker were
freshly prepared in chloroform and protected from light. Then,
thin films were prepared by spin coating (40 s, 2500 rpm) on
the substrates just mentioned using a spin coater (WS-650MZ-
23NPP80, Laurell Technologies) and dried in vacuum for 40
min at room temperature in dark before use.
Patterning
Photolithographic patterns were made in photochemical
chamber (BL-GHX-V, Bilang Biotechnology) using a 1000 W
mercury lamp as the UV-light source. The light intensity (10
mw/cm2 at 254 nm) on the sample surface was maintained
and tracked by spectroradiometer (Solatell, Sola Scope
2000TM). Polymer films on substrates were placed in the
FIGURE 1 FTIR spectra for monomers 1 and 2. [Color figure
can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
1400
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408

JOURNAL OF
POLYMER SCIENCE
WWW.POLYMERCHEMISTRY.ORG
ARTICLE
tion and column chromatography purification procedures, were
highly pure, as confirmed by FTIR, NMR, and elemental analysis
(Figs. (1 and 2)). Monomer 1 showed absorbance at 1022 and
957 cm21 that belonged to the asymmetric stretching of the
PAOAC group in FTIR.12,43 The peak at 1215 cm21 corre-
sponded to P@O stretching.43–45 Monomer 2 showed character-
istic peak of epoxy at 912 cm21, and the peak at 1725 cm21
was attributed to C@O of the ester group.45,46 The isomers of
endo and exo were calculated by NMR based on 1.8 ꢀ 2.4 ppm
(monomer 1) and 6.1–6.3 ppm (monomer 2) respec-
tively.33,40,47,48 It was found that the endo/exo ratio of monomer
1 was 1/1 and 2/1 for monomer 2, which were consistent with
the findings in references very well.33,40,48
Polymerization of the monomers was performed using the
second-generation Grubbs catalyst via ROMP method. The suc-
cessful polymerization could be visually spotted by the increas-
ing viscosity of the reaction mixture after a few hours. Pure
polymers were collected by precipitation in a poor solvent fol-
lowed by drying in vacuum. In copolymerization, the feeding
ratio of two monomers was maintained at 1/1, except for CP3
which has higher content of monomer 1 for the fact that poor
solubility was resulted when more monomer 3 was used. 1H
NMR spectra of the polymers were shown in Figure 2, corre-
sponding well to spectra of their monomers. Relative molecular
weight and PDI were shown in Table 1. The GPC chromato-
graphs were shown in Supporting Information Figure S1. It may
be noted that the seemingly higher PDI of HP2 than other poly-
mers may raise the concern for the adsorption of polymer to
column materials in GPC analysis, but in the separate experi-
ment with varying injecting volumes, this possibility was ruled
out.
Thermal Property
Thermal properties of the synthesized polymers were studied
by DSC and TGA in nitrogen atmosphere. DSC thermographs
were shown in Figure 3, the results were summarized in
Table 1. Generally, all the polymers showed glass transitions
above room temperature except HP5 and CP5. Tg of HP1 was
found at 57 8C, higher than HP2 (51 8C) and HP4 (44 8C).
HP3 showed no transition in the range of scanning tempera-
ture. This is consistent with its hard nature when pressing
with spatula. It is noted that HP3 had very poor solubility in
common organic solvents, such as acetone and THF except in
highly polar solvents such as DMSO and DMF with actually
still limited solubility, indicating high polarity so that the
dipole–dipole interactions may severely interfere with the seg-
ments movement of polymer chain and consequently leading
to high Tg. It may also be related to the hardly avoidable
hydrolysis of small amount of anhydride to carboxylic acid,
and the limited ionic characteristic may be the cause to
increase chain rigidity, and thus lift Tg as found in ionic
complexes.49,50 HP5 showed no glass transition, instead, a
first order transition at lower temperatures, Tm 5 1.2 8C
(DHm 5 234.2 J/g). The transition peaks were both available
during heating and cooling cycles with big supercooling of
36.8 8C. The results suggested melting and crystallization
processes, which is not surprising for the highly flexible chain
FIGURE 2 1H NMR spectra of the synthetic monomers and
polymers. [Color figure can be viewed in the online issue,
which is available at wileyonlinelibrary.com.]
reaction chamber 40 cm underneath the lamp covered by a
photomask preinscribed with patterned windows (Scheme
3). After exposure for a couple of minutes, the patterns were
obtained after development in THF for less than 60 s. Then,
the patterns of microarray were observed and pictured
under an optical microscope (Eclipse Ti-U, Nikon, Japan).
RESULTS AND DISCUSSION
Monomer Synthesis and Polymerization
Norbornene derivative species of monomer 1 and 2 were syn-
thesized conveniently via Diels–Alder cycloaddition reaction
from corresponding starting materials with cyclopentadiene
freshly prepared by thermal cracking its dimer. The resulting
phosphorus-containing monomer
1 and epoxy-containing
monomer 2, having been subjected to rigorous vacuum distilla-
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408
1401

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
TABLE 1 Synthetic Parameters and Thermal Properties of Homopolymers and Copolymers
Entry
M 1 Contenta (%)
Time (h)
Mn
PDI
Tg (8C)
10 wt %loss in 8C
Residualbwt %
HP1
HP2
HP3
HP4
HP5
100
0
7
7.7 3 103
8.1 3 104
/
4.6 3 104
4.0 3 104
1.59
2.31
/
57
51
/
331
367
343
410
405
31
3
9
0
12
10
9
33
6
0
2.28
1.86
44
0
Tm 5 1.2 8C
0
DH 5 34.2 J/g
CP2
CP3
CP4
CP5
50
88
50
50
10
13
10
11
4.6 3 104
1.0 3 104
3.8 3 104
1.9 3 104
2.58
1.36
2.24
2.52
63
342
331
335
328
21
34
27
28
91
52
214, 20
a
b
M 1 content 5 monomer 1/(monomer 1 1 comonomer X).
At 600 8C.
structure of HP5. Copolymers with equimolar (except CP3)
composition of monomer 1 and a comonomer 2, 4–5 showed
more interesting results. Tgs of CP2 and CP4 were at 63 and
52 8C, respectively, close to their corresponding homopoly-
mers. The higher Tg of CP2 than CP4 was probably due to the
bulky side group of monomer 2 compared to 4. CP3 showed
an increased Tg at 91 8C, much higher than HP1 by 34 8C.
Considering the high Tg of HP3 as explained above, the incor-
poration of monomer 3 by only 12% to HP1 backbones hin-
dered the movement of chain segments and so significantly
increased Tg in the copolymer. In contrast, CP5 showed much
lower Tg than HP1. In addition, two Tgs (214 and 20 8C, indi-
cated by arrows in Fig. 3) in broad temperature range (225
to 40 8C) were found, and no melting was observed during
heating in contrast to HP5 because of the incorporation of
monomer 1 to destroy the regularity in backbones. Such a
broad Tg manipulation in PCPs can facilitate the design of
new norbornene based PCPs via ROMP method, for example
in shape-memory applications.51
TGA curves were shown in Figure 4 with the results sum-
marized in Table 1. PCPs typically showed two steps of ther-
mal degradation. The first step was from 313 to 331 8C and
the second from 342 to 613 8C. The former step was mainly
due to loss of ethylene and the second due to CAP bond
according to reference.28 HP4 and HP5 showed mainly one
step process for their simplified C and H chemical composi-
tions. The degradation starting temperatures (when compar-
ing 10 wt % loss in Table 1) of phosphonate homopolymers
and copolymers were mostly lower than HP4 and HP5 by
50–60 8C approximately. This is interesting, because PCPs
were generally thought to be flame retardants instead of
FIGURE 3 DSC traces of homopolymers and copolymers. Two
glass transitions of CP5 were indicated by arrows. [Color figure
can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
FIGURE 4 TGA curves of polymer samples. [Color figure can be
viewed in the online issue, which is available at wileyonlinelibrary.
com.]
1402
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408

JOURNAL OF
POLYMER SCIENCE
WWW.POLYMERCHEMISTRY.ORG
ARTICLE
SCHEME 4 Mechanism of hydrolysis of phosphonate and the resulting crosslinked structure of PCPs (modified based on reference 52).
HP4 and HP5 types of polymers made from C and H only. The
paradox can be explained by the residual wt % after degrada-
tion. At 600 8C, the residual wt % of HP1 was 30%, much
higher than HP4 and HP5 nearly at 0%. The corresponding
copolymers CP4 and CP5 considerably increased residual wt
% by more than 20%, indicating the significant effect from
phosphonated monomer 1. The results for HP2 and CP2 were
very similar to HP4, 5 and CP4, 5. With the results above, it
may be found that thermal stability and flame resistance can
have slightly different meanings in essence, the former was
related to cleavage of chemical bonds and release of volatile
species, while the later was a practical consequence and
mainly related to the ability to retain weight during degrada-
tion at high temperatures. However, the residual wt % of HP3
was quite high, close to HP1. It can be due to the compact and
rigid nature of HP3 as seen by high Tg, which may delay the
decomposition process by hindering the movement of highly
reactive intermediate in matrix during degradation.
Hydrolysis
The PCPs were also tested in hydrolysis to yield phosphonic
acid by treating with trimethylsilyl bromide in dry DCM to
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408
1403

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
hydrolysis was attributed to the stretching of PAOH.45,53,54
However, the solubility of the hydrolyzed samples was much
decreased (Supporting Information Table S1) in contrast to
their ester forms before hydrolysis in most organic sol-
vents.28 The reason could be due to the crosslink process
where phosphonic acid reacted further to form phosphonic
anhydride (Scheme 4).
Applications
Flame-Retarding Experiment
To study the flame-resistant property, the norbornene deriv-
ative PCPs synthesized from ROMP were for the first time
subjected to flame retarding experiment. The results were
shown in Figure 6. When bare print paper was used (blank
test), the combustion was fast and stable till the end.
Curling-up ash was left behind with little weight on. In con-
trast, when the paper was coated with HP1, the combustion
was much slower, and the flame self-extinguished shortly
[Fig. 7(a)]. To be more specifically, the average burning
speed in air quickly decreased from 0.94 cm/s of the blank
paper slip to 0.27 cm/s of the coated specimens. To confirm
the efficiency of flame retardancy, limiting oxygen index
experiment (LOI, according to EN ISO4589-2:1999 and ASTM
D2863-13) was conducted. Blank paper slip quickly burned
at LOI 5 21% at a speed of 1.0 cm/s. In contrast, when
coated with 40 wt % HP1 on the surface, LOI increased and
approached 25% with a much decreased burning speed
<0.1 cm/s. At oxygen concentration 5 35%, the burning
speed was still below 0.5 cm/s which is half of the value of
blank paper. The results indicated that HP1 coating did
retard the flame by an LOI increase of 19% compared to the
FIGURE 5 FTIR of PCPs before and after hydrolysis. [Color fig-
ure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
yield trimethylsilyl esters, which were then cleaved in meth-
anol to afford phosphonic acid. The mechanism is shown in
Scheme 4, partly referring to reference.52 The successful
hydrolysis of PCPs was confirmed by FTIR (Fig. 5). The
broad band between 1060 and 905 cm21 appeared after
FIGURE 6 Digital photographs of the combustion process of print paper without (a) and with (b) HP1 coating. [Color figure can be
viewed in the online issue, which is available at wileyonlinelibrary.com.]
1404
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408

JOURNAL OF
POLYMER SCIENCE
WWW.POLYMERCHEMISTRY.ORG
ARTICLE
FIGURE 7 Digital photograph of the paper coated with HP1 after combustion (a) and the SEM image (b). [Color figure can be
viewed in the online issue, which is available at wileyonlinelibrary.com.]
blank sample. Considering that the specimen was a coated
paper slip with thin HP1 layer on top, and the high inflam-
mability of blank paper, the result should be an averaged
reflection of blank paper and HP1. After complete combus-
tion, the paper slip kept its original shape very well, and had
enough hardness after combustion when pressed (Fig. 7).
Examination of the burned paper showed a clear char layer
on top [Fig. 7(a)], which is typically found in phosphorous-
containing materials indicating the formation of phosphoric
acid and consequently shielding the materials from oxygen.55
SEM showed more morphological details in Figure 7(b). A
gassy surface with many pores breaking through was
observed, indicating the typical intumescent char formation.2
Copolymers showed less flame-retarding efficiency than HP1
because of the lower phosphorous content, and so, cyclotri-
phosphazene of high phosphorous content and should be
anticipated more effective.2 It is interesting to see from liter-
atures that aryl-substituted PCPs are the most studied up to
date besides cyclotriphosphazene-based polymers,2 such as
arylphosphinate,56–58 phenylphosphonate,59,60 phenyl phos-
phate,61 and phenyl-phosphorous amide62 where phospho-
rous was incorporated into the resin of epoxy56,60,62 or
novolacs57 to act as flame-retarding component. Most of
these mentioned PCPs showed LOI from 22 to 40%, except
for a thiol-containing polyphosphonate with a reported high
LOI 5 60% in Ref. 59. It has been known that LOIs of PCPs
are typically proportional to the phosphorus contents (P
%),57 for example, polystyrene with phosphate pending
groups showed typical increase of LOI from 25 to 41% with
P % increasing from 4.97 to 12.79% by weight.61 In a
SCHEME 5 The reactive mechanism of photo-induced crosslink in HP1 via thiol-ene click chemistry. [Color figure can be viewed in
the online issue, which is available at wileyonlinelibrary.com.]
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408
1405

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
FIGURE 8 Optical microscopic photographs of the arrays formed after UV irradiation using a photo mask. The films were tested for
HP1 (a) and CP4 (b) on glass slide substrates. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.
com.]
second example, LOI increased from 24.5 to 34.0% with P %
from 1.50 to 5.20%.57 Nevertheless, P % may not be the
only factor to impact on LOI. In the just mentioned two
examples, Tgs are mostly above 100 8C because of the steric
aryl substitutions and especially after complete curing. In
another example, pheynyl-phosphorous amides of lower Tg
showed lower LOIs than the just mentioned two examples,
that is, LOI 5 28% at P% 5 5.23% with Tg 5 60 8C.62 In this
contribution, P % of HP1-coated paper slip is 5.4% which
resulted in LOI 5 25%, a little lower then reference 62,
where Tg s are relatively close. Take all these results into
successful photo-crosslink process. The results were also
very positive on gold wafers (not shown).
CONCLUSIONS
A series of phosphonated norbornene based homopolymers
and copolymers were synthesized, and their chemical
structures were confirmed by NMR and FTIR. By using
comonomers with epoxy and anhydride moieties, or purely
comonomer of norbornene or cyclopentene, the glass tran-
sition temperatures of the copolymers could be tuned in a
broad temperature range from 214 to 91 8C in this study.
The Tg of phosphonated homopolymer HP1 was at 57 8C,
and increased significantly to 91 8C by copolymerization
with anhydride comonomer 3 (only 12% by content). How-
ever and interestingly, when the phosphonated monomer
was copolymerized with equimolar cyclopentene, two glass
transitions were observed with the lower one only at 214
8C. The results suggest that glass transitions of PCPs can
be conveniently tuned by adjusting the flexibility of como-
nomer to meet the needs in specific applications. Thermal
degradation in nitrogen atmosphere indicated that phos-
phonated polymers started to lose weight 50 8C lower than
polycyclopentene and polynorbornene. This contradicted
with PCPs’ known superior flame-resistant performance
paradoxically. By measuring the residual weight at 600 8C
after degradation, it can be explained by less weight loss in
PCPs, indicating more char generated in PCPs to prevent
combustion. In the followed application studies, norbor-
nene derivative PCPs showed significant flame-retarding
property, and proved to be a promising negative photore-
sist via thiol-ene click chemistry.
consideration, it may reach
a conclusion that LOI of
norbornene-based polyphosphonates is a little lower than
aryl-substituted PCPs probably because the flexible olefinic
backbone of HP1 would be less hindered than aromatic
backbones towards highly reactive intermediates during
combustion on molecular levels.
Photolithography
A second application study was to investigate the ROMP
derived PCPs as photoresists. In recent years, ROMP derived
polymers showed increasing interests in photomicro manu-
facturing area, taking advantage of the highly efficient thiol-
ene click chemistry.35 Recently, it was also successfully
applied in making fine 3D microstructures using two-photon
induced thiol-ene reactive process.63 The convenience of
copolymerization with maleic anhydride derivatives, such as
monomer 3, was regarded as a benefit to obtain high per-
formance photoresist.40 So in this contribution, we for the
first time tested the PCP polymer, HP1, as negative photore-
sist via thiol-ene click chemistry. The mechanism is illus-
trated in Scheme 5, and the result in Figure 8.
The features of the inscribed micro-structure after develop-
ment on the thin film of HP1 were visualized by optical
microscopy using a transmission set-up. Periodic arrays with
sharp contrast can be observed on the film, indicating the
ACKNOWLEDGMENTS
Financial support of the Youth Project from National Natural
Science Foundation of China (No. 21304074), Shaanxi Province
1406
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408

JOURNAL OF
POLYMER SCIENCE
WWW.POLYMERCHEMISTRY.ORG
ARTICLE
26 S. Salzinger, B. Rieger, Macromol. Rapid Commun. 2012,
33, 1327–1345.
Key Laboratory Open Project of Polymer Science and Technol-
ogy (2013SZS17-K01), “100 Talents” Programme from Shaanxi
Province, and the Starting and Innovative Team Programme
from Xi’an University of Technology are gratefully
acknowledged.
€
27 G. W. Rabe, H. Komber, L. Haussler, K. Kreger, G.
Lattermann, Macromolecules 2010, 43, 1178–1181.
€
28 B. Bingol, A. Kroeger, P. Jannasch, Polymer 2013, 54, 6676–
6688.
29 T. Eren, G. N. Tew, J. Polym. Sci. Part A: Polym. Chem.
2009, 47, 3949–3956.
REFERENCES AND NOTES
30 T. Steinbach, E. M. Alexandrino, F. R. Wurm, Polym. Chem.
2013, 4, 3800–3806.
1 R. T. Morrison, R. N. Boyd, Organic Chemistry; Allyn and
Bacon, Inc., Boston, 5 edn., Newton, Massachusetts, 1987,
1393–1400.
31 Y. S. Vygodskii, A. S. Shaplov, E. I. Lozinskaya, O. A.
Filippov, E. S. Shubina, R. Bandari, M. R. Buchmeiser, Macro-
molecules 2006, 39, 7821–7830.
2 H. Liu, X. Wang, D. Wu, Polym. Degrad. Stab. 2014, 103, 96–
112.
32 N. R. Grove, P. A. Kohl, S. A. Bidstrup Allen, S. Jayaraman, R.
Shick, J. Polym. Sci. Part B: Polym. Phys. 1999, 37, 3003–3010.
3 S. Chang, N. D. Sachinvala, P. Sawhney, D. V. Parikh, W.
Jarrett, C. Grimm, Polym. Adv. Technol. 2007, 18, 611–619.
33 D. J. Liaw, C. C. Huang, C. W. Fu, J. Polym. Sci. Part A:
Polym. Chem. 2006, 44, 4428–4434.
4 H. Singh, A. K. Jain, J. Appl. Polym. Sci. 2009, 111, 1115–
1143.
34 D.-J. Liaw, C.-C. Huang, Norbornene Monomers with an
5 A. P. Mouritz, A. G. Gibson, Flame Retardant Composites. In
Fire Properties of Polymer Composite Materials; Springer: Ber-
lin, 2006; Vol. 143, pp 237–286.
Epoxy
Group
and
Polymer
Material
Thereof;
US
20090043059A1, 2009.
35 A. Wolfberger, B. Rupp, W. Kern, T. Griesser, C. Slugovc,
Macromol. Rapid Commun. 2011, 32, 518–522.
ꢀ
6 R. Menard, C. Negrell-Guirao, L. Ferry, R. Sonnier, G. David,
Eur. Polym. J. 2014, 57, 109–120.
36 S. De, A. Khan, Chem. Commun. 2012, 48, 3130–3132.
7 S. Monge, B. Canniccioni, A. Graillot, J. J. Robin, Biomacro-
molecules 2011, 12, 1973–1982.
37 S. De, C. Stelzer, A. Khan, Polym. Chem. 2012, 3, 2342–2345.
38 I. Gadwal, J. Rao, J. Baettig, A. Khan, Macromolecules 2014,
47, 35–40.
8 T. Steinbach, E. M. Alexandrino, C. Wahlen, K. Landfester, F.
R. Wurm, Macromolecules 2014, 47, 4884–4893.
39 I. Gadwal, M. C. Stuparu, A. Khan, Polym. Chem. 2015, 6,
1393–1404.
9 Y. Catel, M. Degrange, L. Le Pluart, P. J. Madec, T. N. Pham,
L. Picton, J. Polym. Sci. A: Polym. Chem. 2008, 46, 7074–7090.
40 A. J. Pasquale, A. R. Fornof, T. E. Long, Macromol. Chem.
Phys. 2004, 205, 621–627.
€
€
10 T. Bock, R. Mulhaupt, H. Mohwald, Macromol. Rapid Com-
mun. 2006, 27, 2065–2071.
41 W. L. Armarego, C. L. L. Chai, Purification of Laboratory
Chemicals. 5 ed.; Butterworth-Heinemann: Boston, 2007.
11 S. V. Kotov, S. D. Pedersen, W. Qiu, Z. M. Qiu, D. J. Burton,
J. Fluorine Chem. 1997, 82, 13–19.
42 K. Ohashi, S. Kosai, M. Arizuka, T. Watanabe, M. Fukunaga,
K. Monden, T. Uchikoda, Y. Yamagiwa, T. Kamikawa, Tetrahe-
dron Lett. 1988, 29, 1189–1192.
ꢁ
12 F. Hacıvelioglu, E. Okutan, S. C¸elik, S. Yes¸ilot, A. Bozkurt, A.
Kılıc¸, Polymer 2012, 53, 3659–3668.
13 J. Li, X. Ni, J. Ling, Z. Shen, J. Polym. Sci. Part A: Polym.
Chem. 2013, 51, 2409–2415.
43 L. Nie, H. Dong, X. Han, G. He, H. Wu, Z. Jiang, J. Power
Sources 2013, 240, 258–266.
14 G. M. Kosolapoff, J. Am. Chem. Soc. 1948, 70, 1971–1972.
15 R. M. Pike, R. A. Cohen, J. Polym. Sci. 1960, 44, 531–538.
44 A. Aslan, A. Bozkurt, J. Power Sources 2012, 217, 158–163.
45 C. G. Cho, S. H. Kim, Y. C. Park, H. Kim, J. W. Park, J.
Membr. Sci. 2008, 308, 96–106.
16 B. J. Muray, J. Polym. Sci. Part C: Polym. Symp. 1967, 16,
1869–1886.
46 N. Sahiner, S. Sagbas, J. Power Sources 2014, 246, 55–62.
17 T. Sato, M. Hasegawa, M. Seno, T. Hirano, J. Appl. Polym.
Sci. 2008, 109, 3746–3752.
47 H. C. Brown, S. Ikegami, D. L. Vander Jagt, J. Org. Chem.
1985, 50, 1165–1171.
18 N. Moszner, F. Zeuner, U. K. Fischer, V. Rheinberger, Macro-
mol. Chem. Phys. 1999, 200, 1062–1067.
48 W. M. Daniewski, C. E. Griffin, J. Org. Chem. 1966, 31,
3236–3241.
19 A. Altin, B. Akgun, Z. Sarayli Bilgici, S. Begum Turker, D.
Avci, J. Polym. Sci. Part A: Polym. Chem. 2014, 52, 511–522.
49 Q. Zhang, C. G. Bazuin, C. J. Barrett, Chem. Mater. 2008, 20,
29–31.
20 N. Moszner, F. Zeuner, S. Pfeiffer, I. Schurte, V.
Rheinberger, M. Drache. Macromol. Mater. Eng. 2001, 286,
225–231.
50 Q. Zhang, X. Wang, C. J. Barrett, C. G. Bazuin, Chem. Mater.
2009, 21, 3216–3227.
51 J. E. Gautrot, X. X. Zhu, Macromolecules 2009, 42, 7324–7331.
21 R. Perrin, M. Elomaa, P. Jannasch, Macromolecules 2009,
42, 5146–5154.
52 G. Feng,The synthesis and characterization of phosphonic
acids for the surface modification study on indium tin oxide;
M.Sc. thesis, Georgia Institute of Technology, 2012.
22 T. Wagner, A. Manhart, N. Deniz, A. Kaltbeitzel, M. Wagner,
G. Brunklaus, W. H. Meyer, Macromol. Chem. Phys. 2009, 210,
1903–1914.
53 A. Oki, L. Adams, V. Khabashesku, Y. Edigin, P. Biney, Z.
Luo, Mater. Lett. 2008, 62, 918–922.
23 F. Jiang, A. Kaltbeitzel, W. H. Meyer, H. Pu, G. Wegner, Mac-
romolecules 2008, 41, 3081–3085.
54 C. Chen, C. Shen, G. Kong, S. Gao, Mater. Chem. Phys.
2013, 140, 24–30.
€
24 D. Markova, A. Kumar, M. Klapper, K. Mullen, Polymer
2009, 50, 3411–3421.
55 I. van der Veen, J. de Boer, Chemosphere 2012, 88, 1119–
1153.
25 U. B. Seemann, J. E. Dengler, B. Rieger, Angew. Chem. Int.
Ed. 2010, 49, 3489–3491.
56 C. H. Lin, C. S. Wang, Polymer 2001, 42, 1869–1878.
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408
1407

JOURNAL OF
POLYMER SCIENCE
ARTICLE
WWW.POLYMERCHEMISTRY.ORG
57 Y. L. Liu, Polymer 2001, 42, 3445–3454.
61 Y. L. Liu, G. H. Hsiue, Y. S. Chiu, R. J. Jeng, C. Ma, J Appl.
Polym. Sci. 1996, 59, 1619–1625.
58 Y. L. Chang, Y. Z. Wang, D. M. Ban, B. Yang, G. M. Zhao,
Macromol. Mater. Eng. 2004, 289, 703–707.
62 R. J. Jeng, S. M. Shau, J. J. Lin, W. C. Su, Y. S. Chiu, Eur.
Polym. J. 2002, 38, 683–693.
59 K. S. Kim, J Appl. Polym. Sci. 1983, 28, 1119–1123.
63 T. Griesser, A. Wolfberger, U. Daschiel, V. Schmidt, A. Fian,
A. Jerrar, C. Teichert, W. Kern, Polym. Chem. 2013, 4, 1708–1714.
60 H. Ren, J. Sun, B. Wu, Q. Zhou, Polym. Degrad. Stab. 2007,
92, 956–961.
1408
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 54, 1396–1408