Investigating phase separation and structural coloration of self-assembled ternary polymer thin films

Abstract

Poly(3-hexylthiophene-2,5-diyl) (P3HT) can generate nanoporous structures with variable pore diameters ranging from 150 to 600 nm from spin-coated blends with polystyrene (PS). In the present study, we observe the effect of the addition of polymethylmethacrylate (PMMA) to P3HT:PS blends to increase the pore-to-pore dimensions up to the micrometer scale. The phase separation in the ternary blend can be directly visualized by replacing the commercial (non-emissive) PS with a boron-dipyrromethene functionalized PS to distinctively locate the red-emitting P3HT and the green-emitting PS phases. In particular, in the ternary blend with high PMMA contents, we observe that PS acts as a compatibilizing agent at the interface between the P3HT and PMMA phases. After selective removal of the PS and PMMA phases using acetone, we demonstrate that, in these P3HT structured thin films, iridescence can be observed as they exhibit angle dependent reflectivity which is further emphasized when covered with a thin metal layer. The metal covered nanostructured P3HT films display bright color switching properties with blue and red emission at low and high reflection angles, respectively.

High-Aspect-Ratio Semiconducting Polymer Pillars for 3D Cell Cultures

“…rr-P3HT nano- and microstructures are typically obtained by self-assembly or by imprinting processes. − If the former approach is not suitable for high aspect ratio structures, the latter requires to heat the solid polymer film well above its glass transition and crystallization temperatures before imprinting (around 170 °C for rr-P3HT) and to apply a controlled pressure on a lithographed hard stamp. By contrast, in our approach, the pillared film is formed from solution, in a few seconds, at room temperature, without any other applied pressure than the weight of the soft PDMS layer, and only a mild thermal treatment is required to facilitate the final stamp detachment.…”

All solution-processed micro-structured flexible electrodes for low-cost light-emitting pressure sensors fabrication

“…In their approach, the carbon nanotubes deposited on top of the pyramid-like PDMS (produced by photolithography) were removed using the scotch-tape peeling method, which is a relatively low-control and low-reproducibility technique. As an alternative to photolithography, we generate micro-porous structures using our recently introduced low-cost polymer self-assembly approach 26 . After depositing blends of Poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly(methyl methacrylate) (PMMA) by spin-coating, the PMMA phase is selectively removed to generate micro-porous structures.…”

“…Self-assembled micro-structured polymer templates were prepared following a method published previously 26 . P3HT (Mw~200,000, Merck) and PMMA (Mw~15,000, Sigma-Aldrich) are mixed in chlorobenzene at a 1:1 ratio and with a total polymer concentration of 30 mg.ml −1 .…”

Strongly Iridescent Hybrid Photonic Sensors Based on Self-Assembled Nanoparticles for Hazardous Solvent Detection

“…The panther chameleons ( Furcifer Pardalis ) can, for instance, change their skin color by modifying the lattice parameters of their iridophores between the excited and the relaxed states [ 10 ]. Various methods for fabricating bio-inspired materials with similar structural coloration properties have been explored over the past two decades, which are either based on lithographic techniques (e.g., electron-beam lithography, imprint lithography, holographic lithography, or two-photon lithography) [ 18 , 19 , 20 , 21 ] or on self-assembled materials [ 22 , 23 , 24 ]. Although lithographic techniques can generate well-defined architectures, colloidal self-assembly has been drawing increasing interest in the field, as it provides a low-cost alternative to fabricating materials with structural coloration properties.…”