Tri-continuous Morphology of Ternary Polymer Blends Driven by ...
Supporting Information
Tri-continuous Morphology of Ternary Polymer Blends Driven by Photopolymerization: Reaction and Phase Separation Kinetics
Toshiya SHUKUTANI, Takahiro MYOJO, Hideyuki NAKANISHI, Tomohisa NORISUYE and Qui TRAN-CONG-MIYATA
*
Department of Macromolecular Science and Engineering Graduate School of Science and Technology Kyoto Institute of Technology Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
*
To whom correspondence should be addressed (Email: [email protected])
1
Synthesis of Poly(ethyl acrylate) doubly labeled with Anthracene and Fluorescein (PEAAF).
The synthesis route for poly(ethyl acrylate) doubly labeled with anthracene as a photo-cross-linker and fluorescein as a marker (PEAAF) is shown in Scheme S1. Prior to polymerization, inhibitor in ethyl acrylate 1 (EA, Wako Pure Chemical Industries, Japan) was removed by washing the monomer respectively with aqueous solutions of sodium sulfite and sodium hydroxide. The purified EA monomer was dried over calcium chloride followed by calcium hydride overnight to remove water, and distilled under reduced pressure.
Ethyl acrylate was polymerized in the presence
of ca. 6 mole% of 2-chloroethyl acrylate 2 (Dajac Labs, Inc) prior to labeling with anthracene (A) and fluorescein derivatives (F).
In order to avoid the formation of
branching structure caused by radical transfer mechanism at high temperature16, the polymerization of the distilled EA was then carried out in acetone with azo-bis-(isobutyronitril) (AIBN, Wako Chemicals, Japan, recrystallized twice in ethanol) as initiator under reflux condition (57 oC) in 30 min.
The resulting PEA was
obtained by precipitation using n-hexane as a non-solvent.
From intrinsic viscosity
data with acetone as solvent at 25 oC, it was found that the resulting PEA has the weight-averaged molecular weight Mw = 83,000.
The polydispersity index Mw/Mn =
2.1 was obtained from GPC measurements using monodisperse polystyrene as standard reference. To doubly label the above-mentioned PEA component with anthracene (A) and fluorescein (F), anhydrous dimethylformide (DMF, Aldrich) was used as a solvent.
At
first, DMF solution of potassium salt of anthracene carboxylic acid was added dropwise 2
into a DMF solution of PEA set at 65 oC and the reaction was carried out for 3h. Subsequently, a DMF solution of fluorescein sodium salt was added dropwise to the solution and the reaction was allowed to proceed for an additional 6 h at 65 oC.
Then,
the reacting solution was poured into iced water to extract the PEA doubly labeled with anthracene and fluorescein (PEAAF).
Finally, the PEAAF was purified using acetone
as a good solvent and a mixture of methanol and distilled water as a non-solvent. polymer was carefully dried under vacuum prior to experiments.
3
The
Scheme S1. Synthesis scheme for poly(ethyl acrylate) doubly labeled with anthracene and fluorescein (PEAAF).
4
Synthesis of Poly(ethyl methacrylate) Labeled with Rhodamine B (PEMAR). The synthesis route for PEMA labeled with rhodamine B is illustrated in Scheme S2.
First, the stabilizer was removed from ethyl methacrylate monomer 3
(EMA, Wako Pure Chemical Industries, Japan) by following the same procedure as described for ethyl acrylate (EA) monomer in the above session.
Subsequently, EMA
was purified by distillation in vacuo using similar procedure for EA monomer.
The
purified EMA monomer was then polymerized in the presence of a trace of methacryloxyethyl thiocarbamoyl rhodamine B 4 (Polyscience Inc,, used without further purification) under vacuo at 65 oC for three days. The resulting polymer bearing the rhodamine group was purified by precipitating using toluene as a good solvent and n-hexane as a non-solvent.
From
intrinsic viscosity measurements using ethyl acetate as good solvent at 35 oC, the weight-average molecular weight of PEMAR is Mw = 1.4 ×105
and the dispersity
index Mw / Mn = 1.6 was obtained from GPC data.
The chemical structures of PEAAF and PEMAR are shown in Schemes S1 and S2 respectively.
The labeling reactions for both PEAAF and PEMAR were confirmed
by using both UV-Vis spectrometry (Shimadzu, Model UV-1600) and fluorometry (Shimadzu, Model RF-5600).
It should be noted that the three polymer components of
the mixture used in this study, poly(ethyl acrylate), poly(ethyl methacrylate) and poly(methyl methacrylate) were chosen as samples because the maximum difference in their refractive indices are less than 1.3 %.
This small difference helps minimizing the
scattering of a laser beam from different domains of the resulting morphology during the scanning process of laser confocal microscopy.
5
As a consequence, all the
phase-separated ternary PEAAF/PEMAR/PMMA mixtures used in this study are almost transparent under visible light.
Scheme S2. Synthesis scheme for poly(ethyl methacrylate) labeled with rhodamine B (PEMAR).
6
Absorption and Fluorescence Spectra of PEEA and PEMAR
Spectra S1. Absorption (-----) and fluorescence (――) spectra of Rhodamine B – labeled poly(ethyl methacrylate) (PEMAR) and poly(ethyl acrylate) labeled with anthracene and fluorescein (PEAAF). Optical filters (colored stripes) for wavelength selection: for excitation (green); for emission (magenta).
7
Figure S1 Three-dimensional view of the “salami” morphology: 1) For binary systems: After 60 min of irradiation with 365 nm, phase separation of rhodamine B-labeled poly(ethyl acrylate) (PEA-R) and poly(methyl methacrylate) (PMMA) was terminated at the “salami” structure shown below after 60 min of photo-polymerization.
Under laser-scanning confocal microscopy, this particular
morphology is the cross-section of the capillary bridges generated by the coupling between the spinodal decomposition followed by secondary phase separation and the wetting phenomena of one polymer component at the sample-glass substrate interfaces.
Fig. S1(a). Orthogonal slices view of 3D image obtained for a “salami” structure of a PEAR/MMA mixture after photo- polymerization of MMA in 60 min. (From Ref. 13).
2) For ternary systems: (K. Nakayama, Y. Takeda, M. Fukuoka, Q. Tran-Cong-Miyata, unpublished results) Similar to binary mixtures, “salami” morphology also emerges in ternary mixtures. The structure is more complex because of the competitions among the three components
Fig. S1(b).
3D image obtained for the “salami” structure of a PEAR/PEMAR/MMA (5/5/90) mixture.
8
of the polymerizing mixture for the wetting.
Experimental conditions are as follows:
1) Samples: A ternary mixture of fluorescein-labeled poly(ethyl acrylate) (PEAF), rhodamine B-labeled poly(ethyl mehacrylate) (PEMAR) and methyl methacrylate (MMA) was used as sample. Its composition is PEAF/PEMAR/MMA (2.5/7.5/90). It should be noted that the PEAF component has a very broad molecular weight distribution (Mw/Mn = 6.6).
Taking into account of broad distribution of molecular weight of the PEAF
component, the emergence of the “salami” structure at low composition of PEAF is in accordance with the morphology map provided in Fig. 2 of the main text. 2) Light intensity: I =0.01 mW/cm2 (at 405 nm). 3) Irradiation time: 60 min (Polymerization yield Φ ~ 90 %), stationary morphology. 4) Experimental temperature: 25 oC. The morphology in the above Figure shows the structures of the “salami” morphology obtained with a ternary PEAF/PEMAR/MMA(2.5/7.5/90) mixture observed along the XY and XZ plans using laser-scanning confocal microscopy.
9
Figure S2 Possibility of the chain transfer reaction to PEAR, PEAAF and PEMAR components of the mixture. 1) Sample: mixtures of rhodamine B-labeled poly(ethyl acrylate) (Mw = 24.3 × 104, Mw/Mn =1.20 ) and methyl methacrylate (MMA). The mixture composition is PEAR/MMA(12/88). 2) Irradiation with 405 nm light to polymerize MMA monomer with Lucirin TPO as an photoinitiator. 3) GPC was used to monitored the molecular weight of the resulting PMMA after 5, 10, 15 and 20 min. before the onset of the Norrish-Trommdorff autoacceleration effect takes place. 4) Experimental temperature: 25 oC. 5) Results: By GPC, the molecular weight of the resulting PMMA was monitored at different irradiation times 0, 5, 10, 15 and 20 min. prior to the onset of the Norrish-Trommsdorff auto-acceleration phenomena. To examine whether, under these experimental conditions, the PMMA chain radicals attack the PEAR chains or not, all the GPC chromatograms
Figure S2. Chromatogram of PMMA undergoing photopolymerization in the presence of PEAR (Solvent: THF; Calibration: standard polystyrenes).
obtained after a given period of irradiation time were monitored during the photopolymerization, and were normalized to the GPC peak height of the initial PEAR component (the second peak on the side of high molecular weight). The results are shown in Figure S2 where it was found that the molecular weight of the resulting PMMA just slightly increases during these time intervals, whereas the distribution of PEAR molecular weight remains unchanged, particularly on the high molecular weight side. (It is worth noting that the high molecular weight component of PMMA generated by the
10
Trommsdorff-Norrish effect has not yet generated at this stage). The slight increase in the molecular weight of PMMA would originate from the decrease in mobility of the polymerizing environment, which in turn gradually delays the termination step of the polymerization.
From the chromatogram shown in
Fig. 9 (in the presence of both PEAAF and PEMAR) of the manuscript and in Fig. S2 (in the presence of PEAR only), the experimental data suggest that, under the experimental conditions of this study, PMMA radicals did not attack either PEAAF or PEMAR chains in the mixture.
11
Figure S3 Tri-continuous morphology of a PEAF /PEMAR/MMA (2.5/7.5/90) mixture. PEAF (branching, Mw = 160,000; Mw/Mn =6.5) (K. Nakayama, Y. Takeda, M. Fukuoka, T. Myojo and Q. Tran-Cong-Miyata, (unpublished results)
The tri-continuous morphology observed in 3D (upper) and in the 2D (XY plan, lower) obtained for a PEAF/PEMAR/MMA(2.5/7.5/90) mixture.
Experimental Conditions: 1) Irradiation intensity: 0.01 mW/cm2 (at 405 nm). 2) Irradiation Time: 60 min (Reaction yield: 90 %), stationary morphology. 3) Morphology: Tri-continuous. 4) Experimental temperature: 25 oC.
12
Tri-continuous Morphology of Ternary Polymer Blends Driven by Photopolymerization: Reaction and Phase Separation Kinetics
Toshiya SHUKUTANI, Takahiro MYOJO, Hideyuki NAKANISHI, Tomohisa NORISUYE and Qui TRAN-CONG-MIYATA
*
Department of Macromolecular Science and Engineering Graduate School of Science and Technology Kyoto Institute of Technology Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
*
To whom correspondence should be addressed (Email: [email protected])
1
Synthesis of Poly(ethyl acrylate) doubly labeled with Anthracene and Fluorescein (PEAAF).
The synthesis route for poly(ethyl acrylate) doubly labeled with anthracene as a photo-cross-linker and fluorescein as a marker (PEAAF) is shown in Scheme S1. Prior to polymerization, inhibitor in ethyl acrylate 1 (EA, Wako Pure Chemical Industries, Japan) was removed by washing the monomer respectively with aqueous solutions of sodium sulfite and sodium hydroxide. The purified EA monomer was dried over calcium chloride followed by calcium hydride overnight to remove water, and distilled under reduced pressure.
Ethyl acrylate was polymerized in the presence
of ca. 6 mole% of 2-chloroethyl acrylate 2 (Dajac Labs, Inc) prior to labeling with anthracene (A) and fluorescein derivatives (F).
In order to avoid the formation of
branching structure caused by radical transfer mechanism at high temperature16, the polymerization of the distilled EA was then carried out in acetone with azo-bis-(isobutyronitril) (AIBN, Wako Chemicals, Japan, recrystallized twice in ethanol) as initiator under reflux condition (57 oC) in 30 min.
The resulting PEA was
obtained by precipitation using n-hexane as a non-solvent.
From intrinsic viscosity
data with acetone as solvent at 25 oC, it was found that the resulting PEA has the weight-averaged molecular weight Mw = 83,000.
The polydispersity index Mw/Mn =
2.1 was obtained from GPC measurements using monodisperse polystyrene as standard reference. To doubly label the above-mentioned PEA component with anthracene (A) and fluorescein (F), anhydrous dimethylformide (DMF, Aldrich) was used as a solvent.
At
first, DMF solution of potassium salt of anthracene carboxylic acid was added dropwise 2
into a DMF solution of PEA set at 65 oC and the reaction was carried out for 3h. Subsequently, a DMF solution of fluorescein sodium salt was added dropwise to the solution and the reaction was allowed to proceed for an additional 6 h at 65 oC.
Then,
the reacting solution was poured into iced water to extract the PEA doubly labeled with anthracene and fluorescein (PEAAF).
Finally, the PEAAF was purified using acetone
as a good solvent and a mixture of methanol and distilled water as a non-solvent. polymer was carefully dried under vacuum prior to experiments.
3
The
Scheme S1. Synthesis scheme for poly(ethyl acrylate) doubly labeled with anthracene and fluorescein (PEAAF).
4
Synthesis of Poly(ethyl methacrylate) Labeled with Rhodamine B (PEMAR). The synthesis route for PEMA labeled with rhodamine B is illustrated in Scheme S2.
First, the stabilizer was removed from ethyl methacrylate monomer 3
(EMA, Wako Pure Chemical Industries, Japan) by following the same procedure as described for ethyl acrylate (EA) monomer in the above session.
Subsequently, EMA
was purified by distillation in vacuo using similar procedure for EA monomer.
The
purified EMA monomer was then polymerized in the presence of a trace of methacryloxyethyl thiocarbamoyl rhodamine B 4 (Polyscience Inc,, used without further purification) under vacuo at 65 oC for three days. The resulting polymer bearing the rhodamine group was purified by precipitating using toluene as a good solvent and n-hexane as a non-solvent.
From
intrinsic viscosity measurements using ethyl acetate as good solvent at 35 oC, the weight-average molecular weight of PEMAR is Mw = 1.4 ×105
and the dispersity
index Mw / Mn = 1.6 was obtained from GPC data.
The chemical structures of PEAAF and PEMAR are shown in Schemes S1 and S2 respectively.
The labeling reactions for both PEAAF and PEMAR were confirmed
by using both UV-Vis spectrometry (Shimadzu, Model UV-1600) and fluorometry (Shimadzu, Model RF-5600).
It should be noted that the three polymer components of
the mixture used in this study, poly(ethyl acrylate), poly(ethyl methacrylate) and poly(methyl methacrylate) were chosen as samples because the maximum difference in their refractive indices are less than 1.3 %.
This small difference helps minimizing the
scattering of a laser beam from different domains of the resulting morphology during the scanning process of laser confocal microscopy.
5
As a consequence, all the
phase-separated ternary PEAAF/PEMAR/PMMA mixtures used in this study are almost transparent under visible light.
Scheme S2. Synthesis scheme for poly(ethyl methacrylate) labeled with rhodamine B (PEMAR).
6
Absorption and Fluorescence Spectra of PEEA and PEMAR
Spectra S1. Absorption (-----) and fluorescence (――) spectra of Rhodamine B – labeled poly(ethyl methacrylate) (PEMAR) and poly(ethyl acrylate) labeled with anthracene and fluorescein (PEAAF). Optical filters (colored stripes) for wavelength selection: for excitation (green); for emission (magenta).
7
Figure S1 Three-dimensional view of the “salami” morphology: 1) For binary systems: After 60 min of irradiation with 365 nm, phase separation of rhodamine B-labeled poly(ethyl acrylate) (PEA-R) and poly(methyl methacrylate) (PMMA) was terminated at the “salami” structure shown below after 60 min of photo-polymerization.
Under laser-scanning confocal microscopy, this particular
morphology is the cross-section of the capillary bridges generated by the coupling between the spinodal decomposition followed by secondary phase separation and the wetting phenomena of one polymer component at the sample-glass substrate interfaces.
Fig. S1(a). Orthogonal slices view of 3D image obtained for a “salami” structure of a PEAR/MMA mixture after photo- polymerization of MMA in 60 min. (From Ref. 13).
2) For ternary systems: (K. Nakayama, Y. Takeda, M. Fukuoka, Q. Tran-Cong-Miyata, unpublished results) Similar to binary mixtures, “salami” morphology also emerges in ternary mixtures. The structure is more complex because of the competitions among the three components
Fig. S1(b).
3D image obtained for the “salami” structure of a PEAR/PEMAR/MMA (5/5/90) mixture.
8
of the polymerizing mixture for the wetting.
Experimental conditions are as follows:
1) Samples: A ternary mixture of fluorescein-labeled poly(ethyl acrylate) (PEAF), rhodamine B-labeled poly(ethyl mehacrylate) (PEMAR) and methyl methacrylate (MMA) was used as sample. Its composition is PEAF/PEMAR/MMA (2.5/7.5/90). It should be noted that the PEAF component has a very broad molecular weight distribution (Mw/Mn = 6.6).
Taking into account of broad distribution of molecular weight of the PEAF
component, the emergence of the “salami” structure at low composition of PEAF is in accordance with the morphology map provided in Fig. 2 of the main text. 2) Light intensity: I =0.01 mW/cm2 (at 405 nm). 3) Irradiation time: 60 min (Polymerization yield Φ ~ 90 %), stationary morphology. 4) Experimental temperature: 25 oC. The morphology in the above Figure shows the structures of the “salami” morphology obtained with a ternary PEAF/PEMAR/MMA(2.5/7.5/90) mixture observed along the XY and XZ plans using laser-scanning confocal microscopy.
9
Figure S2 Possibility of the chain transfer reaction to PEAR, PEAAF and PEMAR components of the mixture. 1) Sample: mixtures of rhodamine B-labeled poly(ethyl acrylate) (Mw = 24.3 × 104, Mw/Mn =1.20 ) and methyl methacrylate (MMA). The mixture composition is PEAR/MMA(12/88). 2) Irradiation with 405 nm light to polymerize MMA monomer with Lucirin TPO as an photoinitiator. 3) GPC was used to monitored the molecular weight of the resulting PMMA after 5, 10, 15 and 20 min. before the onset of the Norrish-Trommdorff autoacceleration effect takes place. 4) Experimental temperature: 25 oC. 5) Results: By GPC, the molecular weight of the resulting PMMA was monitored at different irradiation times 0, 5, 10, 15 and 20 min. prior to the onset of the Norrish-Trommsdorff auto-acceleration phenomena. To examine whether, under these experimental conditions, the PMMA chain radicals attack the PEAR chains or not, all the GPC chromatograms
Figure S2. Chromatogram of PMMA undergoing photopolymerization in the presence of PEAR (Solvent: THF; Calibration: standard polystyrenes).
obtained after a given period of irradiation time were monitored during the photopolymerization, and were normalized to the GPC peak height of the initial PEAR component (the second peak on the side of high molecular weight). The results are shown in Figure S2 where it was found that the molecular weight of the resulting PMMA just slightly increases during these time intervals, whereas the distribution of PEAR molecular weight remains unchanged, particularly on the high molecular weight side. (It is worth noting that the high molecular weight component of PMMA generated by the
10
Trommsdorff-Norrish effect has not yet generated at this stage). The slight increase in the molecular weight of PMMA would originate from the decrease in mobility of the polymerizing environment, which in turn gradually delays the termination step of the polymerization.
From the chromatogram shown in
Fig. 9 (in the presence of both PEAAF and PEMAR) of the manuscript and in Fig. S2 (in the presence of PEAR only), the experimental data suggest that, under the experimental conditions of this study, PMMA radicals did not attack either PEAAF or PEMAR chains in the mixture.
11
Figure S3 Tri-continuous morphology of a PEAF /PEMAR/MMA (2.5/7.5/90) mixture. PEAF (branching, Mw = 160,000; Mw/Mn =6.5) (K. Nakayama, Y. Takeda, M. Fukuoka, T. Myojo and Q. Tran-Cong-Miyata, (unpublished results)
The tri-continuous morphology observed in 3D (upper) and in the 2D (XY plan, lower) obtained for a PEAF/PEMAR/MMA(2.5/7.5/90) mixture.
Experimental Conditions: 1) Irradiation intensity: 0.01 mW/cm2 (at 405 nm). 2) Irradiation Time: 60 min (Reaction yield: 90 %), stationary morphology. 3) Morphology: Tri-continuous. 4) Experimental temperature: 25 oC.
12
