TY - GEN
T1 - Facile fabrication of uniaxial nanopatterns on shape memory polymer substrates using a complete bottom-up approach
AU - Chen, Zhongbi
AU - Krishnaswamy, Sridhar
PY - 2014
Y1 - 2014
N2 - In earlier work, we have demonstrated an assisted self-assembly fabrication method for unidirectional submicron patterns using pre-programmed shape memory polymers (SMP) as the substrate in an organic/inorganic bilayer structure. In this paper, we propose a complete bottom-up method for fabrication of uniaxial wrinkles whose wavelength is below 300 nm. The method starts with using the aforementioned self-assembled bi-layer wrinkled surface as the template to make a replica of surface wrinkles on a PDMS layer which is spin-coated on a pre-programmed SMP substrate. When the shape recovery of the substrate is triggered by heating it to its transition temperature, the substrate has been programmed in such a way that it shrinks uniaxially to return to its permanent shape. Consequently, the wrinkle wavelength on PDMS reduces accordingly. A subsequent contact molding process is carried out on the PDMS layer spin-coated on another pre-programmed SMP substrate, but using the wrinkled PDMS surface obtained in the previous step as the master. By activating the shape recovery of the substrate, the wrinkle wavelength is further reduced a second time in a similar fashion. Our experiments showed that the starting wavelength of 640 nm decreased to 290 nm after two cycles of recursive molding. We discuss the advantages and limitations of our recursive molding approach compared to the prevalent top-down fabrication methods represented by lithography. The present study is expected to o er a simple and cost-effective fabrication method of nano-scale uniaxial wrinkle patterns with the potential for large-scale mass-production.
AB - In earlier work, we have demonstrated an assisted self-assembly fabrication method for unidirectional submicron patterns using pre-programmed shape memory polymers (SMP) as the substrate in an organic/inorganic bilayer structure. In this paper, we propose a complete bottom-up method for fabrication of uniaxial wrinkles whose wavelength is below 300 nm. The method starts with using the aforementioned self-assembled bi-layer wrinkled surface as the template to make a replica of surface wrinkles on a PDMS layer which is spin-coated on a pre-programmed SMP substrate. When the shape recovery of the substrate is triggered by heating it to its transition temperature, the substrate has been programmed in such a way that it shrinks uniaxially to return to its permanent shape. Consequently, the wrinkle wavelength on PDMS reduces accordingly. A subsequent contact molding process is carried out on the PDMS layer spin-coated on another pre-programmed SMP substrate, but using the wrinkled PDMS surface obtained in the previous step as the master. By activating the shape recovery of the substrate, the wrinkle wavelength is further reduced a second time in a similar fashion. Our experiments showed that the starting wavelength of 640 nm decreased to 290 nm after two cycles of recursive molding. We discuss the advantages and limitations of our recursive molding approach compared to the prevalent top-down fabrication methods represented by lithography. The present study is expected to o er a simple and cost-effective fabrication method of nano-scale uniaxial wrinkle patterns with the potential for large-scale mass-production.
KW - self-assembly
KW - shape memory polymer
KW - wrinkle
UR - http://www.scopus.com/inward/record.url?scp=84902097116&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84902097116&partnerID=8YFLogxK
U2 - 10.1117/12.2045755
DO - 10.1117/12.2045755
M3 - Conference contribution
AN - SCOPUS:84902097116
SN - 9780819499844
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Behavior and Mechanics of Multifunctional Materials and Composites 2014
PB - SPIE
T2 - Behavior and Mechanics of Multifunctional Materials and Composites 2014
Y2 - 10 March 2014 through 12 March 2014
ER -