Encapsulation of π-Conjugated Polymer Nanocrystals and Their Ordered Array Structure toward Photonic Nanomaterials

Abstract

Polydiacetylene (PDA) nanocrystals were successfully encapsulated by soap-free copolymerization of styrene monomer and hydrophilic styrene derivative. The resulting polystyrene-encapsulated PDA nanocrystals became almost uniform and spherical and could be arranged conveniently on a patterned substrate using the tapered cell method. These basic processes to fabricate ordered array structure on a substrate are very important toward photonic devices application made up of PDA nanocrystals in the near future. In addition, the formation mechanisms for encapsulation were discussed in detail.

Hybridized Organic Nanocrystals for Optically Functional Materials

“…123 However, these techniques cannot be unexpected to produce an ordered array structure for organic NCs. On the contrary, the present combination of above-mentioned techniques (A) to (C) would be definitively superior to the previous methods in the cases of organic NCs, 90,92 including polymer microspheres (or polymer colloidal particles) and colloidal silica particles. Figure 22 shows typical patterned Si(100) substrates, which were prepared by electron beam (EB) lithography and subsequent anisotropic wet etching.…”

“…123126 However, there are mainly two problems to realize this. 92 One is that the shape of organic NCs is usually not )spherical but cubic or rectangular, and the other is commonly the size distribution. To overcome and dissolve these problems, our attention is now intensively focused on (A) encapsulation of organic NCs, 92 (B) the use of lithographically patterned substrate, 90 and (C) the employment of so-called tapered cell method.…”

“…92 One is that the shape of organic NCs is usually not )spherical but cubic or rectangular, and the other is commonly the size distribution. To overcome and dissolve these problems, our attention is now intensively focused on (A) encapsulation of organic NCs, 92 (B) the use of lithographically patterned substrate, 90 and (C) the employment of so-called tapered cell method. 115,116 Encapsulation may provide some merits: pseudomonodisperse in size of organic NCs, spherical shape, and passivation effect for stable dispersion.…”

“…This process could be basically repeated to further trap PSMSs on the first layer of ordered PSMS array structure as a template. 90,92 5.1 Ordered Array Structure of PSMS. Ordered array structure could be designed conveniently by optimizing the parameters of L and P, pattern symmetry, and the diameter (D) of PSMS.…”

“…92 Namely, CdS and ZnS NPs dispersion liquids were refluxed at 80°C under nitrogen atmosphere by adding styrene (St) monomer, divinylbenzene (DVB) as a crosslink agent, and potassium peroxodisulfide (KPS) initiator, followed by purification using centrifugation instrument, and then redispersed in an aqueous dispersion medium. As a result, CdS and ZnS NPs were successfully encapsulated with transparent and weakly crosslinked polystyrene (PS) shell, i.e., PS-encapsulated CdS and ZnS microparticles (MPs), as shown in Figure 30.…”