The aging phenomena of a poly(ether ether keton) (PEEK) surface hydrophilically modified via various protocols was investigated. The use of plasma treatment or chemical etching methods offers a relatively convenient surface modification route. However, the effects of hydrophilic treatment quickly disappeared and its original surface property was recovered within a few hours or a few days when stored at ambient conditions. Surface treatment based on a single-layered chemical grafting method rendered an excellent hydrophilic surface with an initial contact angle of <158 and an improved retardation of surface aging. However, the contact angle of the modified PEEK specimen gradually increased with time and eventually reached 508 after 23 days. A new method for the long-term stable hydrophilic surface treatment of PEEK using a multilayered chemical grafting strategy was also developed. With this regard, aging of the modified surface could be significantly retarded over 90 days. It was believed that the effectiveness of the surface modification and the retarded aging phenomena via the multilayered hydrophilic treatment could be attributed to mechanical and chemical stability of the covalently bonded active surface groups on the grafted polymer networks. V C 2017 Wiley Periodicals, Inc. J.Appl. Polym. Sci. 2018, 135, 46042.

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CH 3 NH 3 PbBr 3 (MAPbBr 3 ) MHP-NPs can be synthesized by reprecipitation of an MAPbBr 3 solution and subsequent stabilization of the produced MAPbBr 3 NPs with ligands. [5] Huang et al. reported that monodispersed MAPbBr 3 MHP-NPs with tunable sizes can be synthesized by introducing an emulsifier such as tert-butanol in the reprecipitation method. [6] Zhang et al. synthesized bright MAPbX 3 (X = Cl, Br, and I) MHP-NPs by the ligand-assisted reprecipitation (LARP) method using n-octylamine and oleic acid co-ligands. [7] Gonzalez-Carrero et al. reported that MAPbBr 3 MHP-NPs without oleic acid long-alkyl ligands could be synthesized by adjusting the molar ratio between the total ammonium salts and PbBr 2 and the octylammonium bromide/MABr/1octadecene molar ratio. [8] Recently, Kim et al. reported that bright MAPbBr 3 MHP-NPs beyond quantum sizes can be synthesized by the reprecipitation method using n-hexylamine and oleic acid co-ligands. [9] Very recently, Park et al. reported that postprocessable MAPbX 3 MHP-NPs can be prepared by the modified LARP method using a reduced amount of N,Ndimethylformamide (DMF) and co-ligands of n-hexylamine and oleic acid. [10] Although a wealth of studies on the synthesis of organic/ inorganic hybrid MHP-NPs have been performed in batch reactor systems, the stability of MHP-NPs must be improved to commercialize practical applications because they have intrinsically poor stability against moisture due to their ionic crystal structure. Therefore, they should be passivated or encapsulated by moisture tolerance materials such as metal oxides and polymers. [11][12][13][14][15][16][17] MHP-NPs encapsulated by polymers can remain flexible due to the flexible polymer matrix, and consequently, they have great potential in diverse applications.So far, MHP-NPs encapsulated by polymers have been synthesized by two separate batch reactions, which are a synthesis process of MHP-NPs in a batch reactor and a separate encapsulation process of the produced MHP-NPs in the batch reactor. [18][19][20][21][22] Hence, it remains challenging to develop a continuous process unifying the two independent synthetic processes. Herein, we investigate a one-step microfluidic synthesis, which enables in situ production of MHP-NPs by LARP and encapsulation of MHP-NPs in cross-linked polymer microspheres by UV curing. The MHP-polymer composite microparticles show enhanced air and moisture stability because they were produced with highly cross-linked hydrophobic polymer. Waterproof light-emitting perovskite-polymer composite microparticles are synthesized by a continuous one-step microfluidic reactor, which enables in situ production of metal halide perovskite nanoparticles (MHP-NPs) by the ligand-assisted reprecipitation process (LARP) and the encapsulation of MHP-NPs by UV cross-linking polymerization in the microfluidic channel. Successful encapsulation of MHP-NPs in polymer microparticles is attributed to the co-dispersion of an LARP solution and UV polymerizable solution in an aqueous continuous phase within ...

A one‐step strategy to fabricate magnetically stirrable microparticles with geometric/chemical anisotropies via a microfluidic technique combined with partial phase separation is presented. Monodisperse oil‐in‐water microemulsions composed of magnetite nanoparticles (MNPs) and two polymers, polystyrene and poly(d,l‐lactide‐co‐glycolide) (PLGA), dissolved in chloroform are generated using the microfluidic method. Upon incubating the microemulsions in pure water at ambient conditions, the solvent contained in the microemulsions is gradually removed and partial phase separation between the two polymers occurs spontaneously. In the meantime, the microemulsion droplets are vertically aligned due to the density difference of the two polymer phases. During the spontaneous phase separation, the MNPs become unstable and the aggregated MNPs segregate downward by gravity to the denser PLGA phase. After complete removal of the solvent, the resulting particles adopt geometric/chemical anisotropies, and they are magnetically rotatable under an external magnetic field. It is demonstrated that the morphology of the anisotropic particles can be controlled readily by adjusting the ratio of the two polymers as well as the concentration of MNPs. It is believed that the developed method based on the partial phase separation and the gravity‐induced segregation of the MNPs enables large‐scale production of magnetically stirrable microparticles.

Strong electrostatic repulsive forces between PMMA particles in CHB/decane mixtures were directly measured with optical laser tweezers.