Abstract
We present a method for fabricating photonic crystals (PCs) by polymerization-induced microphase separation of block copolymers (BCPs). Molecular weight of BCP for PCs is so large that it has been difficult for conventional solution casting and annealing methods to complete the microphase separation to form periodically ordered submicron structures. Our method overcomes the difficulty by inducing the microphase separation and transitions during the polymerization, when the molecular weight of the BCPs is small enough for the microphase separation and transitions. The microphase-separated structure is then enlarged while maintaining the self-similarity. We succeeded in fabricating PCs with reflection wavelength λm ≈ 1000 nm and a full width at half-maximum Δλ = 0.05λm by living-radical bulk block copolymerization of poly(methyl methacrylate)-block-polystyrene.
Highlights
Photonic crystals (PCs) are materials containing a periodic structure with a length scale of hundreds of nanometers.[1−3] PCs reflect visible light selectively in accordance with Bragg’s law of diffraction
The gel permeation chromatography (GPC) chart at tp = 0 min is from poly(methyl methacrylate) (PMMA)-reversible addition−fragmentation chain transfer (RAFT) and at tp ≥ 60 min are from polymerized PMMA-block-PS
We overcame the problem of strong chain entanglement in large molecular weight Block copolymers (BCPs) for fabricating PCs by the polymerization-induced microphase separation method
Summary
Photonic crystals (PCs) are materials containing a periodic structure with a length scale of hundreds of nanometers.[1−3] PCs reflect visible light selectively in accordance with Bragg’s law of diffraction. The SANS profile was reproduced by substituting the fitting parameters in Table 1 into eqs 5−10, where NBCP, NHP, and φBCP were referred to these estimated from Mw and CM around tp = 30 min and φHP to a previously reported value.[38] The χ value of 0.008 was much smaller than the literature values of 0.028− 0.055.47,53−55 considering the sensitive trend of χ on degree of polymerization,[56,57] which decreases from 0.055 to 0.028 as NBCP increases from 130 to 330,47,53−55 the χ value in our BCP with NBCP = 4000 is in line with the literature values.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
