Interfacial Engineering of Polymer Blend with Janus Particle as Compatibilizer

Mixing two or more polymers to produce the“polymer alloy”is one of the most versatile and economical strategies for developing new polymeric materials.The compatibility between polymer components largely determines the comprehensive performance of polymer blend.More recently,a type of unique surface partitioned materials,Janus particles,has been proposed to act as a novel interfacial compatibilizer for polymer blends.Such Janus particles integrates the amphipathicity of diblock copolymer and interfacial stabilization of nanoparticles,displaying a significant superiority in comparison with molecular compatibilizers for a wide range of polymer blends.In this review,we mainly focus on the compatibilizing effects of Janus nanofillers of various morphologies,including spherical,snowman-like,and two-dimensional nanosheets,on polymer blends.We shed light on the impacts of compatibilization of Janus particles on phase morphologies,mechanical properties,and functionalities of polymer blends.This review could provide a guidance for designing an effective Janus particle compatibilizer to develop high-performance polymer blends.

Polymer/Metal Segmental Janus Nanoparticles

Polymer/metal composite segmental Janus nanoparticles （NPs） are synthesized by sequential growth against poly（4-vinylpyridine） （P4VP） crosslinked cP4VP-PS Janus NPs. A Janus cluster of poly（4-vinylpyridine）-block-polystyrene （P4VP-b-PS） diblock copolymer is self-organized after absorption onto a silica patchy sphere via hydrogen bonding. Selective crosslinking of P4VP leads to the formation of robust cP4VP-PS Janus NPs. Within the cP4VP domain, functional species such as metals are preferentially grown by in situ reduction. Other thiol-capped polymers, for example, thiol-capped poly（N-isopropylacrylamide） （PNIPAM-SH）, can be conjugated onto the opposite side to form polymer/metal triple segmental Janus NPs. The hyperthermia effect ofAu NP of PNIPAM-Au@cP4VP-PS by near infrared （NIR） irradiation can trigger a fast transition from amphiphilic to hydrophobic of the Janus NPs at low surrounding temperature. De-stabilization of the emulsion is NIR triggered although the system temperature is below LCST （-32 ℃）.

pH responsive Janus polymeric nanosheets

pH responsive polymeric Janus nanosheets with poly（maleic acid） moiety and crosslinked PS onto the corresponding sides have been synthesized by free radical polymerization. The Janus nanosheets can serve as solid emulsifier to stabilize an oil/water emulsion, whose stability is easily triggered by changing pH across pKa of the poly（maleic acid）.

Ionic liquid functionalized polymer composite nanotubes toward dye decomposition

Poly（ionic liquid） functionalized composite nanotubes are achieved by ATRP grafting ionic liquid monomers for example ViEtIm^＋Br^- from the poly（DVB-co-VBC） nanotubes surface. PW12O40^3- anion is introduced through anion exchange. The PW12O40^3- based composite nanotubes can synchronously absorb and decompose water soluble dyes for example methyl orange（MO）. The cooperative interplay is promising in highly efficient decomposition of dyes.

Cable-like Au@SiO2 Janus composite nanorods

Cable-like Au@SiO2 Janus composite nanorods with PS and PEG grafting on both ends respectively are fabricated by skiving in combination of a post favorable modification. The cable-like Au@SiO2 composite nanofibers are synthesized in the channel of porous anodic aluminium oxide （AAO） membrane. After skiving, the corresponding composite nanorods are obtained. Following, PEG-SH and PS-SH are conjugated onto the two ends of the nanorods by a selective partial modification, respectively. Length and diameter of the Au@SiO2 Janus composite nanorods can be tuned controllably. It can be extended to fabricate a variety of different Janus nanorods with different compositions and microstructures.