A s hape memory porous sponge with tunability in both surface wettability and pore size for
smart molecule release
Pengchang Liu1#, Hua Lai1#, Qixing Xia3, Dongjie Zhang1, Zhongjun Cheng1*, Yuyan Liu1* and Lei Jiang2
1 MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China
2 CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 P.R.
China
3 Institute of culture and heritage, Northwest Polytechnical University, Xi’an 710000, China
* Corresponding author (email: chengzhongjun@iccas.ac.cn, liuyy@hit.edu.cn )
Figure S1. Schematic illustration of the control process of the shape recovery and the
parameters for the calculation of the Rs. (a) The SMS is in the original state with the initial thickness of h0. After being pressed at 70 ℃ and cooling under a certain pressure (about 4.5×103 Pa) to room temperature, the SMS can memorize the pressed state and the thickness is decreased to h1, and this state is defined as the pressed state.
Then the pressed SMS was put into a mould with two parallel plates, and the distance between the two plates (d) can be adjusted accurately (c). After setting the distance between the two plates, the sample was further heated at 70 ℃ to trigger the shape recovery of the SMS. After the recovery process and further cooling to room temperature. The sample was taken out from the mould and the thickness of the SMS in this state (hx) would be equal to d. In this work, h0 =3 cm, h1= 0.5 cm, hx was measured, and then, according to the equation (1) in the experimental section, the Rs can be obtained. Moreover, because d is controllable and can be adjusted arbitrarily, SMS with diverse Rs can be obtained.
h0 After pressing
h1
Put in the mold Cooling in RT
Put in the mold for shape recovery
hx hx
mold
d
a) b) c)
d) e)
Figu
supe sect
ure S2. S
erhydrophil tion.
Schematic lic shape m
illustration emory spon
of prepar nge (SMS),
ration proc the detailed
cess of th d process se
he PPy co ee experime
oated ental
Figu
TPI vibr PU PDA obse
ure S3.
I-PDA/PEI- ration of C=
sponge, wh A/PEI was d
erved, prov
The FT-IR PU sponge
=C in the TP hich can end deposited o ving that TPI
R spectra e. The peak
PI proves th dow the spo n the TPI-P I has a good
of the P ks at the 1 hat the TPI onge with t PU sponge, d stability in
PU spong 1665 cm-1 a
has been su the shape m
the peaks in n the synthe
e, TPI-PU assigned to uccessfully memory prop
n the 1665 c esis process
U sponge o the stretc
coated onto perty. When cm-1 can sti s.
and hing o the n the ill be
Figure S4. (a) The XPS spectra of the pure PU (black line), after coating of TPI (red
line), and after further coating of PDA/PEI (dark yellow line), respectively. (b), (c) and (d) are XPS spectra of the PDA/PEI, pure TPI and PPy, respectively. From these figures, it can be seen that because there is no N element in TPI (c), when the PU is coated with the TPI, the element N was disappeared (red line in a), indicating that the TPI has been coated on the PU sponge. After further coating with the PDA/PEI, the reappearance of the elemental N was observed, and this is due to the presence of N in the PDA/PEI (b), further confirming the successful coating of PDA/PEI. After further coating with the PPy, the appearance of the elemental S and F were observed, and this is due to the presence of S and F in the PPy (d).
250 300 350 400 450 500 0
3000 6000 9000
Intensity (a.u.)
Binding energy (eV)
PDA/PEI
250 300 350 400 450 500
Intensity (a.u.)
Binding Energy (eV) PU sponge PU sponge+TPI
PU sponge+TPI+PDA/PEI
C N
250 300 350 400 450 500 0
3000 6000 9000
Intensity (a.u.)
Binding energy (eV)
TPI
a) b)
c)
0 200 400 600 800 1000 1200 0
3000 6000 9000
Intensity (a.u.)
Binding energy (eV) S
C
N O
F
d)
Figu
view ima mod surf poro surf furth and
ure S5. SEM
w (a) and b age of the
dification o face of the ous structur face is chan her modific the average
M images o bottom view original P of PDA/PEI
original PU re can be r nged. After cation of PD
e size of the
of the PU sp w (b) SEM i
PU sponge I, respective U sponge is remained. H
coating of DA/PEI, lot e nanopartic
ponge durin images of t e, (d) after ely. From t smooth, af However, t the TPI, so ts of nanopa cle is about
ng different the original r coating o these figure fter coating the microstr ome wrinkl
articles can 500 nm (e)
preparation PU sponge of TPI, (e es, it can b of TPI and ructure on es can be f be formed .
n processes e, (c) magn e) after fur be seen that d PDA/PEI
the framew found (d). A d on the surf
: top ified rther t the , the work After face,
Figu
spon of th The prop The Rr= Rf= Wh and
ure S6. (a)
nges treated he sponge a e schematic
perty.
e Rr and Rf w
=hfషhr
hfషh0
hfషh0 hiషh0
ere hf is the hi is the tem
Statistic of d by the TP after treated c illustration
were calcula e fixed thick mporary thi
f shape reco I solutions d by the sol n of the te
ated accordi kness, hr is t ckness.
overy ratio with differe lution with est process
ing to the fo the recovere
(Rr) and sh ent TPI con TPI concen for heating
ollowing equ ed thickness
hape fixing r centration.
ntration of g-triggered
uations:
s, h0 is the in
ratio (Rf) of (b) SEM im 30 mg ml-1
shape mem
（1 （2 nitial thickn
f the mage
1. (c) mory
）
） ness,
From shap on spon (a).
spon abou
Figu
(d) PPy PPy
m the Figu pe memory the Rr (the nges have s When the nge would ut 20 mg m
ure S7. (a-c
Dependenc y onto the S y on the spo
ure S6, it ca property o e shape rec similar Rr), TPI concen
be blocked ml-1.
c) SEM ima ce of the wa SMS. It can onge surfac
an be seen of the spong covery actu
while its in ntration is in d (b). Thus,
ages of the P ater contact
be seen tha e is increas
that the co ge. The TPI ually comes ncrease can d
ncreased to , in our wo
PPy on to th angle on th at as the rea sed. When t
oncentration I concentrat from the directly resu
about 30 m ork, the TPI
he SMS dur he reaction action time i the reaction
n of TPI is tion has no
sponge, thu ult in the in mg ml-1, som
I concentra
ring differen time during is increased n time is abo
crucial for apparent e us all prep ncrease of th
me pores of ation is fixe
nt reaction t g the coatin d, the amoun
out 60 min r the
ffect pared he Rf
f the ed at
time.
ng of nt of , the
surf 2°, i
Figu
PPy dop sma the by c M, t betw
face can be indicating t
ure S8. We
y as differen ping of the P
all amount ( surface wet changing th the PPy wa ween superh
totally cove hat the supe
ettability sw nt amount PFOS ion, th
(0.005 M) o ttability cou he applied p
as in a highl hydrophobic
ered by the erhydrophob
witching be of PFOS io he surface w of PFOS ion uld switch b otentials. W ly doped sta city and sup
PPy, and th bicity has b
etween the on is doped wettability a n was introd between hyd When the co
ate, and its perhydrophi
he water con been produc
oxidation a d. These re always keep duced, the P drophobicit oncentration surface we ilicity.
ntract angel ed.
and reductio sults indica ps the hydro PPy was pa ty and surpe n of PFOS io ttability cou
l reaches 15
on states of ate that wit
ophilic. Wh artly doped, erhydrophil on reached uld be switc
50±
f the thout hen a , and licity 0.02 ched
Figure S9. (a) Dependence of the water contact angle on the reduction time. (b) Dependence of the water contact angle on the oxidation time.
Figure S10. Nitrogen adsorption-desorption isotherms of SMS with diverse Rs: (a) Rs=20%, (b) Rs=40%, (c) Rs=60%, (d) Rs=80%, (e) Rs=100% respectively.
0 10 20 30 40 50 60 0
40 80 120 160
WCA/deg.
Time (min) 0 10 20 30 40 50 60
0 40 80 120 160
WCA/deg.
Time (min)
a) b)
0.0 0.2 0.4 0.6 0.8 1.0 0
100 200 300
Relative pressure (P/P0) Quantity absorption / (cm3 g-1STP)
Absorption Desorption
0.0 0.2 0.4 0.6 0.8 1.0 0
100 200 300
Relative pressure (P/P0) Quantity absorption / (cm3g-1STP)
Absorption Desorption
0.0 0.2 0.4 0.6 0.8 1.0 0
100 200 300
Relative pressure (P/P0) Quantity absorption / (cm3g-1STP)
Absorption Desorption
0.0 0.2 0.4 0.6 0.8 1.0 0
100 200 300
Relative pressure (P/P0) Quantity absorption / (cm3g-1STP)
Absorption Desorption
a) b) c)
d)
Rs=20% Rs=40% Rs=60%
Rs=80%
0.0 0.2 0.4 0.6 0.8 1.0 0
100 200 300
Quantity absorption / (cm3g-1STP)
Relative pressure (P/P0) Absorption
Desorption
e)
Rs=100%
Figure S11. The pore size of SMS at different state: (a) Rs =0%, (b) Rs =20%, (c) Rs
=40%, (d) Rs =60%, (e) Rs =80%, and (f) Rs =100%, respectively. It can be seen that as the Rs is increased, the pore size is increased, demonstrating that the shape memory effect of the SMS can help it to memorize different pore size.
Figure S12. Compressive stress-strain curves of the SMS with strains up to 85% for
880 885 890 895 900 905 910 0.0
0.2 0.4 0.6 0.8
Pore width (μm) Incremental pore volume (cm3/g)
0.6 0.9 1.2 1.5 1.8 2.1 0.0
0.2 0.4 0.6 0.8 1.0
Incremental Pore Volume (cm3/g)
Pore Width (μm)
2 3 4 5 6
0.0 0.2 0.4 0.6 0.8 1.0
Pore Width (μm) Incremental Pore Volume (cm3/g)
27 30 33 36 39
0.0 0.2 0.4 0.6 0.8 1.0
Incremental Pore Volume (cm3/g)
Pore Width (nm) 81 84 87 90 93 96 99
0.0 0.2 0.4 0.6 0.8
Pore Width (μm) Incremental Pore Volume(cm3/g)
14 16 18 20 22 24 26 28 30 32 34 0.0
0.2 0.4 0.6 0.8 1.0
Incremental Pore Volume (cm3/g)
Pore Width (nm)
Rs=0% Rs=20% Rs=40%
Rs=60% Rs=80% Rs=100%
a) b) c)
d) e) f)
0 20 40 60 80
0.000 0.006 0.012 0.018
Unloading Loading
Stress (MPa)
Strain (%)
Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 Cycle 6 Cycle 7 Cycle 8 Cycle 9 Cycle 10
ten
Figu
oxid afte rem spon
cycles.
ure S13. T
dation/reduc er pressing/r mained and nge surface
Top view ( ction the PP recovering f the PPy pa e.
(a) and bot Py layers 20 for 20 cycle article and
ttom view 0 cycles, (c)
es. It is clea PDA/PEI p
(b) SEM ) and (d) ar ar see that t particle has
images of e SEM ima the porous s s the good
the SMS ages of the S
structure ca stability in
after SMS an be n the
Figu goo
Figu of S
ure S14. Ph od shape me
ure S15. St SMS at diffe
hotograph o emory prope
tatistic resu erent Rs.
0 0 15 30 45
W C A /de g.
of the SMS erty, and can
lts about w
0 20
with differ n memorize
ater contact
40 60 Rs (%)
rent Rs, ind e different sh
t angle (WC
0 80 )
icating that hapes.
CA) for the
100
t the SMS h
bottom sur has a
rface
Figu
perm be s can resp elec Liq
The liqu grav calc spon exp
ure S16. T
meation film seen that wa
be retaine ponse to ctrochemica quid permea
e SMS was uid was add vity of the culated acco nge, S is th eriment, the
The water m: (a) Photo
ater can pas d as the PP
alternating al potentials
ation exper
firstly fixed ded into th
liquid with ording to F=
he area of e height of t
permeation ographs of t ss through th
Py is in the oxidation .
riment
d under a g e tube, the hout any ex
=V/St, here the glass t the column
n process the device f he film as t e oxidate s n (plus si
glass tube to e permeation xternal assi e, V is recor
tube, and t was hold co
control by for control o the PPy is in state. (b) Th ign) and
o obtain a m n process w stance. The rded liquid is the perm onstant at 1
y using the of water per n the reduct he water fl reduction
measuremen was carried e permeatio volume tha meation tim
0 cm.
e SMS as rmeation, it tive state, w lux variatio
(minus s
nt device. T d out under on flux (F) at permeates me. During
the t can while on in
sign)
Then r the
was s the this
Figure S17. Shape memory quantitative cycle for TPI. Shape recovery ratio=
(ε-εr)/( ε-εi)×100%. From the figure, it can be calculated that the shape recovery ratio of the TPI is about 97.5%, meaning that the TPI has good shape memory ability.
0 5 10 15 20 25 30
0 200 400 600 800 1000
Time (min)
0.00 0.03 0.06 0.09 0.12
20 40 60 80
Str ain ( % ) Stress ( M Pa) Te mperature ( ℃ )
Figure S18. Storage modulus and loss tangent (tan θ) as a function of temperature
obtained from dynamic mechanical analysis. The TPI modulus in the room temperature is about 116.84 MPa, when the SMS is heated above 60 ℃, the modulus is about 0.22 MPa.
10 20 30 40 50 60 70 80 90 100 0.00
0.15 0.30 0.45 0.60
tan
tan
Storage modulus
0 50 100 150
Storage modulus (MPa)
Temperature ( ℃ )
Figu
corr the amo F an evid resp only mat
ure S19. S
responding EDX in the ounts of F a nd S eleme dence for th pectively. Fr
y be observ terials can o
SEM imag element ma e selected ar and S eleme ents were d he PFOS ion rom the cro ved in the only be pres
ges of SMS appings of
rea (with ye ents existed detected in n doping an
ss-sectional top layer o ent on the t
S in the o F and S fro ellow wiref d in the oxid
the reduce nd de-doping
l images, it of the spong
top surface o
oxidation a om PFOS io frames). It c dized state ( ed state (b) g at oxidatio
can be seen ge surface, of the spong
and reducti ons were ob can be seen (a), but sma , thereby p on and redu n that eleme meaning t ge.
ion states.
btained thro that signifi aller amoun providing d uction poten ents F and S that the coa
The ough icant nts of direct ntials, S can
ating
Figure S20. Statistic results about porosity for SMS at different Rs. It can be seen that as the Rs is increased, the porosity is increased.
0 20 40 60 80 100 0
20 40 60 80 100
Po ro s it y ( % )
Rs(%)
Figure S21. Statistic results about the pore size for SMS with different original
thickness at Rs=0 % (at pressed state) when the PPy shows superhydrophobicity (a) and superhydrophilicity (b), respectively. Firstly, one can observe that the superhydrophobic/superhydrophilic switching of PPy has no remarkable effect of the effective pore size of the whole sponge. Secondly, it can be seen that when the sponge thickness is too small (for example 1 cm), at the pressed state, the pore size (both PPy with superhydrophobicity and superhydrophilicity) is about 21 μm. When the thickness is increased to about 2 cm, the pore size is still higher than 100 nm. When the thickness is further increased to 3 cm, one can found that the pore size is about 28 nm, means that a wide range regulation of the pore size from several hundred of microscale meters to dozens of nanoscale meters can be obtained. In this work, the thickness of the original sponge is fixed at 3 cm to provide a large regulation range of the pore size.
1 2 3
0.0 0.1 16 18 20 22 24
Pore size (μm)
Thickness (cm)
Superhydrophobic
1 2 3
0.0 0.1 16 18 20 22 24
Pore size (μm)
Thickness (cm)
Superhydrophilic
a) b)
Figure S22 Diagrammatic drawing of molecule delivery system based on the SMS.
The control of molecule release
To exhibit the molecule release, the SMS was mounted on the bottom of a vessel containing 0.5 mg mL-1 Rh B solution (10 mL), as shown in Figure S21. Then, the vessel was dipped into a reservoir with 40 mL water. The liquid surfaces of the solution in the vessel and reservoir were controlled on the same horizontal plane, thus ensuring that small molecule can transport from the vessel into the reservoir but water molecules could not. In the solution, the weak gravity produced by the Rh B molecules was negligible. Because of the concentration gradient, the Rh B molecules could release from the vessel into the reservoir through the SMS. To perform the cumulative concentration of Rh B molecules released amounts test, 1.5 mL of released solution in the reservoir was taken out for analysis. Then, the absorbance of molecule solution was detected by measuring the UV-visible absorption spectra with PerkinElmer spectrophotometer, and the concentration of each solution could be determined according to the Lambert-Beer Law.[1] To ensure the liquid surfaces of solution in and out of the vessel were at the same level, an addition of 1.5 mL water
Vessel Reservoir
Small molecular
SMS
was added into the reservoir after each solution was sampled. To carry out the pulsatile release, each electrochemical potential was applied to the SMS for 3600 s. A three-electrode system involved a SMS as the working electrode, and a platinum foil and Ag/AgCl electrode served as the counter and reference electrodes, respectively.
During the application of the electrochemical potential, the electrolyte in the reservoir was replaced by an acetonitrile solution containing 0.02 M PFOS ion.
Reference
1 Wang Y, Jing X, Effect of solution concentration on the UV-vis spectroscopy measured oxidation state of polyaniline base. Polym Test, 2005, 24:153-156
