![Page 1: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/1.jpg)
Nano-channel Creation in a Polymer Thin Film Studied by GISAXS
Xuefa Li, Christopher K. OberSol M. Gruner, Detlef-M Smilgies
Lewis Fetters
Dept. of Materials Science & EngineeringDept. of Physics
CHESS
![Page 2: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/2.jpg)
The Idea
CC H 2
C H 2
C H 2C H 2
C H 2
C H 3
C H 3
C H 3
C H
C HC
Cx
yn m
b
1 2
A two-step strategy was developed to create nano-channels: In step 1 a low-doseUV was used to crosslink the matrix. In step 2 a high-dose UV was used to decompose the cylinder phase.
![Page 3: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/3.jpg)
AFM Results
2 m
Before UV exposure After UV exposure
2 m
Poly(isoprene-b--methylstyrene) diblock copolymer:Cylinders stand up in the thin film (left). After poly(-methylstyrene) blocks were selectively decomposed by UV exposure, hydrophobic nano-channels were created (right).
![Page 4: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/4.jpg)
GISAXS Scattering Geometry-I
CCD
CCD
side view
top view
beamstop
α: incident angleβ: exit angleψ: scattering angle
S1S2S3
![Page 5: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/5.jpg)
GISAXS Scattering Geometry-II
qz
q
thin filmSurface plane
Scattering plane
diffuse XR:normal density profile
SAXS:lateral surfacestructure
![Page 6: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/6.jpg)
Nano-channel Creation-I
Poly(isoprene-b--methylstyrene) diblock copolymer:Hydrophobic nano-channels form in the thin film and still stand up after poly(-methylstyrene) blocks were selectively decomposed by UV exposure.
Before UV exposure After UV exposure
![Page 7: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/7.jpg)
Nano-channel Creation-II
Before UV exposure After UV exposure
Poly(hydroxy-styrene-b--methylstyrene) diblock copolymer:Hydrophilic nano-channels form in the thin film and stand up after poly(-methylstyrene) blocks were selectively decomposed by UV exposure.
![Page 8: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/8.jpg)
Effect of Photo-crosslinker
Before UV after UV
A thin film without photo-crosslinker shows standing-up cylinders before exposeto UV. After UV decomposes poly(-methylstyrene) block, the nano-channelscollapse due to the soft matrix. Therefore, a photo-crosslinker is essential.
![Page 9: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/9.jpg)
Annealing Effect
Fresh film 2 hr annealing 24 hr annealing
Poly(isoprene-b--methylstyrene) block copolymer in freshly spin-coatedthin film forms standing-up cylinders. After annealing, the cylinders tend to lie parallel to the substrate.
![Page 10: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/10.jpg)
Application of GISAXS
Micelleson substrate
Cylindersparallel to substrate
Mixed lamellar domainsparallel and normalto substrate
![Page 11: Nano-channel Creation in a Polymer Thin Film Studied by GISAXS Xuefa Li, Christopher K. Ober Sol M. Gruner, Detlef-M Smilgies Lewis Fetters Dept. of Materials](https://reader030.vdocuments.us/reader030/viewer/2022032708/56649e5c5503460f94b54485/html5/thumbnails/11.jpg)
Summary
Poly(isoprene-b--methylstyrene) diblock copolymer forms standing-upcylinders in the thin films. With added photo-crosslinker, the poly(isoprene) matrix can be selectively crosslinked and poly(-methylstyrene) block can be decomposed by using a two-step UV exposure strategy. The nano-channels were created as proved by both AFM and GISAXS.
AcknowledgementCCMR and NSF for financial support
CHESS, CNF and CCMR for facility uses.Prof. Gruner group