Supporting Information
of
Thermo-sensitive Ionic Microgels via Post Quaternization Cross-Linking:
Fabrication, Property, and Potential Application
Xianjing Zhou a, Jingjing Nie b, Junting Xu a, Binyang Du a*
a
MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer
Science & Engineering, Zhejiang University, Hangzhou 310027, China
b
Department of Chemistry, Zhejiang University, Hangzhou 310027, China
A
B
m : n = 25 : 3
Mn = 4.2*104
PDI = 2.0
1
5
4
7, 8, 9
9
8
7
6
5
4
6
3 2
3
2
1
0
in ppm
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
log Mw
Fig. S1 (A) 1H NMR (400MHz, D2O) and (B) GPC curve of linear copolymer P (NIPAm-co-VIM).
Fig. S1A shows the 1H NMR spectrum of P(NIPAm-co-VIM). The characteristic signals δ = 1.07 ppm
and δ = 3.83 ppm could be ascribed to 6H of -(CH3)2 group and 1H of (-CH-) for NIPAm, and δ = 6.6~7.6
ppm could be ascribed to 3H of imidazole ring for VIM. The integral intensities of the peaks at δ = 3.83
ppm and δ = 6.6~7.6 ppm were used to calculate the content of each monomer in the copolymer, i.e.
*
Corresponding author. E-mail: duby@zju.edu.cn
1
[NIPAm] : [VIM] = 25 : 3 (molar ratio).
B
A
1
Mn = 2.3*104
PDI = 1.5
m : n = 20 : 3
5, 6, 7, 8
9
8
7
4
6
5
4
3 2
3
2
1
3.5
0
in ppm
4.0
4.5
5.0
5.5
log Mw
Fig. S2 (A) The 1H NMR spectrum and (B) GPC curve of the obtained P (NIPAm-co-4VP).
Fig. S2A shows the typical 1H-NMR spectrum of P(NIPAm-co-4VP) copolymer. The characteristic
signals of NIPAm and 4VP moieties were δ = 8.37 ppm and δ = 7.10 ppm [2H and 2H of pyridine group]
for 4VP, δ = 1.06 ppm [6H of -(CH3)2 group] and δ = 3.85 ppm [1H of isopropyl group] for NIPAm,
respectively. The signals at δ = 1.44 ppm and δ = 1.96 ppm were belonged to the 2H and 1H in the
(-CH2CH-) groups of both NIPAm and 4VP moieties.
B
1200
heating
cooling
1000
800
600
400
200
0
20
30
40
50
o
Temperature ( C)
60
Intensity Weighted (a.u.)
Hydrodynamic Radius (nm)
A
100
80
60
40
20
100
80
60
40
20
100
80
60
40
20
0
40oC PDI=0.105
100
1000
o
50 C PDI=0.166
100
1000
o
60 C PDI=0.180
100
1000
Hydrodynamic Radius (nm)
2
Fig. S3 (A) The hydrodynamic radius of linear copolymer P(NIPAm-co-4VP) in aqueous solution as a
function of measuring temperature. (B) The corresponding size distribution measured by DLS at 40 °C,
50 °C, and 60 °C, respectively.
Fig. S4 The photo pictures of quaternization reaction products with sample codes of TS1#-40-6,
TS2#-50-6, TS3#-60-6, TS4#-70-6, TS5#-60-5, and TS6#-60-4 from left to right, respectively.
A
-9
B
TS2#-50-6
TS3#-60-6
TS4#-70-6
-10
-9.2
TS 5#-60-5
TS 6#-60-4
-9.4
-9.6
-1
Ln I
Ln I
-1
-11
-12
-9.8
-10.0
-10.2
-13
-10.4
-14
1
2
3
2
4
4
-2
q *10 (nm )
5
-10.6
2.5
3.0
3.5
4.0
2
4.5
4
5.0
5.5
6.0
-2
q *10 (nm )
Fig. S5 Guinier-type plots of LnI(q)-1 ~ q2 measured by SLS at 25C for (A) P(NIPAm-co-VIM)/1,
6-dibromohexane microgels and (B) P(NIPAm-co-VIM)/1, 4-dibromobutane microgels and P
(NIPAm-co-VIM)/ 1, 5-dibromopentane microgels. The solid lines were linear fits.
The SLS data could be well described by Guinier-type plots of LnI(q)-1 ~ q2 as shown in Fig.S5, where
I is the scattering intensity and q = (4πn/λ) sin(θ/2), with λ, n, and θ being the wavelength of the laser light
3
in vacuum (here λ = 637 nm), the refractive index of solvent, and the scattering angle, respectively. Rg
could be then calculated from the slope of LnI(q)-1 ~ q2 via the equation given as:
LnI  q   LnI  0  
1
1
Rg
3
2
q2
(S1)
Fig. S6 TEM images of the P(NIPAm-co-4VP)/1, 4-dibromobutane microgels prepared at various
temperatures. (A) PNV-5 prepared at 60 oC, (B) PNV-2 prepared at 50 oC, and (C) PNV-6 prepared at 40
o
C.
0.5
Absorbance (a.u.)
0.4
6
Abs = 4.181*10 * c
2
R = 0.9994
0.3
0.2
0.1
0.0
0
2
4
6
8
10
-8
Concentration (*10 mol/mL)
Fig. S7 The standard curve for UV absorbance of K2Cr2O7 obtained by measuring a series of K2Cr2O7
aqueous solutions with various concentrations in the range of 0~10-7 mol/mL.
4
Langmuir model:
𝑄𝑒 =
𝐾𝐿 × 𝑞𝑚 × 𝐶𝑒
1 + 𝐾𝐿 × 𝐶𝑒
(1)
Where, Qe is the solid-phase adsorbate concentration at equilibrium, Ce is the adsorbate concentration in
the aqueous phase at equilibrium. qm is the theoretical maximum monolayer adsorption capacity of the
adsorbent (mg/g), KL is the Langmuir isotherm constants.
Freundlich model:
𝑛
𝑄𝑒 = 𝐾𝐹 × 𝐶𝑒 𝐹
(2)
Where, Qe is the solid-phase adsorbate concentration at equilibrium, Ce is the adsorbate concentration
in the aqueous phase at equilibrium. KF is the Freundlich isotherm constant, and NF is the
heterogeneity factor.
The sum of the squares of the errors (SSE):
SSE = ∑(𝑄𝑐 − 𝑄𝑒 )2
(5)
Where, Qe is the solid-phase adsorbate concentration at equilibrium, Qc is the calculated concentration at
equilibrium.
Table S1 The correlation coefficients (R2), sum of the squares of the errors (SSE) and corresponding
fitting parameters of various adsorption isotherm models for the adsorption of K2Cr2O7 onto the ionic
microgels.
Langmuir
Freundlich
R2
SSE
qm(mg/g)
KL(L/mg)
R2
SSE
KF(L/g)
nF
0.877
1439.7
211
0.002
0.953
428.1
5.737
0.467
5
Hydrodynamic radius (nm)
300
250
TS 3#-60-6
TS naphthalene
200
150
100
o
VPTT=37 C
50
0
20
30
40
50
60
70
o
Temperature ( C)
Fig. S8 The hydrodynamic radius of TS-naph and TS3#-60-6 microgels as a function of measuring
temperature.
6