UV-solvent annealing of PDMS-majority and PS-majority PS-b-PDMS block copolymer films

Abstract

The response of polystyrene-block-poly(dimethylsiloxane) (PS-b-PDMS) thin films to UV exposure during solvent vapor annealing is described, in order to improve their applicability in nanolithography and nanofabrication. Two BCPs were examined, one with the PS block as majority (f = 68%, M = 53 kg mol), the other with PDMS block as majority (f = 67%, M = 44 kg mol). A 5 min UV irradiation was applied during solvent vapor annealing which led to both partial crosslinking of the polymer and a small increase in the temperature of the annealing chamber. This approach was effective for improving the correlation length of the self-assembled microdomain arrays and in limiting subsequent flow of the PDMS in the PDMS-majority BCP to preserve the post-anneal morphology. Ordering and orientation of microdomains were controlled by directed self-assembly of the BCPs in trench substrates. Highly-ordered perpendicular nanochannel arrays were obtained in the PDMS-majority BCP.

Synthesis, molecular characterization and self-assembly of (PS-b-PDMS)n type linear (n = 1, 2) and star (n = 3, 4) block copolymers

“…Complex structures such as the ones exhibited by the star block copolymers in this study have potential for a variety of applications and especially as thin films in nanotechnology since controlled orientation is feasible, and therefore may minimize further the molecular weight limits towards nanotechnology applications and directed self-assembly features as already reported in previous studies for PS-b-PDMS diblock copolymers. 6,26,[44][45][46][47][48]…”

In Situ Tracking of Composition and Morphology of a Diblock Copolymer Film with GISAXS during Exchange of Solvent Vapors at Elevated Temperatures

“…Moreover, solvent condensation at the walls of the setup must be avoided. New promising approaches involving STVA comprise microwave heating and laser heating during solvent vapor annealing and UV irradiation to partially cross‐link the achieved morphology …”

“…Moreover, statistically relevant information is obtained within less than a second, i.e., not only on the structure and its repeat distance, but also on the degree of long‐range order and on coexisting structures. This new approach allows one to “navigate” through the phase diagram, until a desired BCP thin film morphology is reached, and fix it, e.g., by rapid drying or cross‐linking by UV irradiation . As a model system, we choose a thin film from a compositionally asymmetric PS‐ b ‐PDMS diblock copolymer, which forms PDMS cylinders in a PS matrix.…”

Lab-on-a-chip device made by autohesion-bonded polymers

“…The proposed PEEK-PS microfluidic system demonstrated a highly effective production process through the plasma treatment on targeted surface and compression for self-adhesion. Unlike PDMS-PS (Arias-Zapata et al 2016 ; Lee et al 2016 ), no solvent chemicals are required. A solvent-free self-assembled dimensionally-stable PEEK-PS microfluidic system is possible.…”