Facile phase transfer of gold nanorods and nanospheres stabilized with block copolymers Facile phase transfer of gold nanorods and nanospheres stabilized with block copolymers

Morphological transition between hexagonal and lamellar patterns in thin polystyrene–block–poly(4-vinyl pyridine) films simultaneously exposed to a strong in-plane electric field and saturated solvent vapor is studied with atomic force and scanning electron microscopy. In these conditions, standing cylinders made of 4-vinyl pyridine blocks arrange into threads up to tens of microns long along the field direction and then partially merge into standing lamellas. In the course of rearrangement, the copolymer remains strongly segregated, with the minor component domains keeping connectivity between the film surfaces. The ordering tendency becomes more pronounced if the cylinders are doped with Au nanorods, which can increase their dielectric permittivity. Non-selective chloroform vapor works particularly well, though it causes partial etching of the indium tin oxide cathode. On the contrary, 1,4-dioxane vapor selective to polystyrene matrix does not allow for any morphological changes.

We describe the synthesis and physical-chemical properties of new anisotropic derivatives of terphenyl. They have been prepared by the modification of corresponding 3,6-disubstituted cyclohex-2-enone and the interaction with ethyl ester of 6-bromohexanoic acid. The synthesised compounds: 4ʹʹ-((1s, 4r)-4-butylcyclohexyl)-2ʹ-chloro-[1,1ʹʹ:4ʹ,1ʹʹ-terphenyl]-4-ol (TERPh-OH), 6-((4ʹʹ-((1s, 4r)-4-butylcyclohexyl)-2ʹ-chloro-[1,1ʹ:4ʹ,1ʹʹ-terphenyl]-4-yl)oxy)hexanoic acid (TERPh-COOH) and 8-((4ʹʹ-((1s, 4r)-4-butylcyclohexyl)-2ʹ-chloro-[1,1ʹ:4ʹ,1ʹʹ-terphenyl]-4-yl)oxy)oct-1-en-3-one (TERPh-VK) were used for the preparation of liquid crystals and their properties were studied. TERPh-COOH is capable of interacting with inorganic nanoparticles providing thus a tool for the creation new nanocomposite materials. TERPh-VK demonstrates the ability to polymerise with the formation of a LC polymer. Graphical Abstract

In the present research, we have synthesized new vinyl ketone monomers with mesogenic substituents, namely, 8-(3′-chloro-4′-pentyl-[1,1′-biphenyl-4-oxy)oct-1-en-3-one (BVK) and 8-[2′-chloro-4‴-octyl-[1,1′:4′,1″:4″,1‴-quaterphenyl-4-oxy]oct-1-en-3-one (QVK). The comparison of BVK, QVK, and previously synthesized 8-((4″-((1R,4S)-4-butylcyclohexyl)-2′-chloro-[1,1′,4′,1″-terphenyl]-4-yl)oxy)oct-1-en-3-one (TVK) has revealed that all of them are able to form crystals, while their ability to exhibit liquid crystalline behavior depends on the number of phenyl substituents attached to the para-position of the phenoxy group and is observed for TVK and QVK only. All of the monomers are able to achieve self-polymerization upon heating and free radical polymerization in bulk or in solution under the action of the common radical initiator AIBN. We have also succeeded in the RAFT polymerization of the synthesized vinyl ketones BVK and TVK using asymmetrical trithiocarbonates. The synthesized poly(vinyl ketones) exhibit LC behavior and are able to undergo photodegradation upon UV irradiation.