Morphology control of poly(styrene-block-dimethylsiloxane) by simple blending with trimethylsilylated silicate nanoparticles
Ginam Kim, Steven Swier, Hae-Jeong Lee, Chengqing Wang
Trimethylsilylated silicate nanoparticle (MQ resin)/poly(styrene-block-polydimethylsiloxane) (PS-PDMS, 31k-15k, P.D=1.15 Mw=45.5 K) blends behave similarly to block copolymer with different PS/PDMS ratios. MQ is localized in the PDMS phase virtually extending the volume fraction in the block copolymer. This allows for micro-domain morphology control beyond what can be achieved with the starting block copolymer. Synthesizing siloxane-containing block copolymer targeted at certain equilibrium morphologies can be time-consuming and in some cases technically challenging. The convenient and robust structure control MQ nano-particle modification of PS-PDMS provides could overcome one of the hurdles to adoption of block copolymer lithography. Solubility parameters, thermal analysis and microscopic techniques confirm the high affinity of MQ for the PDMS phase. For example, PS-PDMS with an equilibrium morphology having hexagonally arrayed PDMS cylindrical phases in a polystyrene matrix can be blended with MQ resin to attain a co-continuous morphology, also termed gyroid morphology, and a lamellar morphology depending on the level of MQ modification. This work shows that MQ is a robust morphology modifier, not limited by the occurrence of surface segregation and the high diffusion rates typically associated with homopolymer modification, as confirmed by looking at the PDMS/PS-PDMS reference. At very high MQ loadings, corresponding to over 70vol% MQ in the siloxane phase, further morphological control becomes challenging. Arguments will be made for a possible nano- particle saturation limit and diffusion limitations.
, Swier, S.
, Lee, H.
and Wang, C.
Morphology control of poly(styrene-block-dimethylsiloxane) by simple blending with trimethylsilylated silicate nanoparticles, Macromolecules
(Accessed March 4, 2024)