Liquid/Liquid Interfacial Fabrication of Thermosensitive and Catalytically Active Ag Nanoparticle-Doped Block Copolymer Composite Foam Films

Liu, Mei,Wang, Qian,Geng, Yuanyuan,Wang, Changwei,Lee, Yong-Ill,Hao, Jingcheng,Liu, Hong-Guo American Chemical Society 2014 Langmuir Vol.30 No.34

<P>An aqueous solution of AgNO<SUB>3</SUB> (upper phase) and a DMF/CHCl<SUB>3</SUB> solution of polystyrene-<I>b</I>-poly(acryl acid)-<I>b</I>-polystyrene (PS-<I>b</I>-PAA-<I>b</I>-PS) or PS-<I>b</I>-PAA-<I>b</I>-PS/1,6-diaminohexane (DAH) (lower phase) constituted a planar liquid/liquid interface. The lower phase gradually transformed to a water-in-oil (W/O) emulsion via spontaneous emulsification due to the “ouzo effect”. Polymer molecules, DAH molecules, and Ag<SUP>+</SUP> ions assembled into microcapsules around emulsion droplets that adsorbed at the planar liquid/liquid interface, resulting in formation of a foam film. DAH acted as a cross-linker during this process. Transmission electron microscopic observations indicated that Ag nanoclusters that were generated through reduction of Ag<SUP>+</SUP> ions by DMF were homogeneously dispersed in the walls of the foam structure. X-ray photoelectron spectroscopic investigations revealed that Ag(I) and Ag(0) coexisted in the film, and Ag(I) transformed to Ag(0) after further treatment. The film formed without DAH was not stable, while the film formed with DAH was very stable due to intermolecular attraction between PAA and DAH and formation of amides, as revealed by FTIR spectra. The film formed with DAH exhibited high and durable catalytic activity for hydrogenation of nitro compounds and, very interestingly, exhibited thermoresponsive catalytic behavior.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2014/langd5.2014.30.issue-34/la502738j/production/images/medium/la-2014-02738j_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la502738j'>ACS Electronic Supporting Info</A></P>

Polyethyleneimine-functionalized phenolphthalein-based cardo poly (ether ether ketone) membrane for CO2 separation

Yunwu Yu,Junhai Wang,Yan Wang,Wenhao Pan,Changwei Liu,Peng Liu,Lianjie Liang,Changwei Xu,Yunxue Liu 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.83 No.-

Phenolphthalein-based cardo poly(ether ether ketone) (PEEKWC)/polyethyleneimine (PEI) crosslinkingmembranes were prepared by solution casting followed by solution reaction at room temperature. Theeffects of reaction time and PEI content on the membrane structure and gas separation performanceswere investigated. Light transmittance measure and AFM evidenced the relationship between themicrophase separation in PEEKWC-PEI membranes and reaction time. The CO2 permeability increasedwith the PEI content, while the N2 and CH4 permeability remained nearly constant. This result indicatedthat only CO2 was transported by the solution–diffusion mechanism and also that PEI exhibited a positivecontribution as afixed carrier for CO2 facilitated transport. Meanwhile the PEEKWC-PEI crosslinkingmembranes showed higher selectivities than the pure PEEKWC membrane. The highest CO2/N2 and CO2/CH4 selectivities were about 131 and 122 increasing from 33 and 30, respectively. The crosslinkingstructure of membranes improved the CO2 permeability stability.

A Computed Tomography Analysis of the Success of Spinal Fusion Using Ultra-Low Dose (0.7 mg per Facet) of Recombinant Human Bone Morphogenetic Protein 2 in Multilevel Adult Degenerative Spinal Deformity Surgery

Gabriel Liu,Jun Hao Tan,Changwei Yang,John Ruiz,Hee-Kit Wong 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.6

Study Design: Retrospective cohort study. Purpose: To report on spinal fusion assessment using computed tomography (CT) after adult spinal deformity (ASD) surgery using ultra-low dose recombinant human bone morphogenetic protein 2 (RhBMP-2). Overview of Literature: The reported dose of RhBMP-2 needed for successful spinal posterolateral fusion in ASD ranges from 10 to 20 mg per spinal level. This study reports the use of ultra-low dose of RhBMP-2 (0.07 mg per facet) to achieve spinal fusion in multilevel ASD surgery. Methods: Consecutive patients who underwent ASD surgery using ultra-low dose RhBMP-2 were recruited. Routine postoperative CT analysis for spinal fusion was performed by two spine surgeons. Inter-observer agreement was calculated for facet fusion (FF) and interbody fusion (IBF) at 6 and 12 months after the procedure. Results: Six consecutive ASD patients with a mean age of 62 years (28–72 years) were examined. Each patient received a total dose of 12 mg with an average dose of 0.69±0.2 mg (0.42–1 mg) per single FF and 1.38±0.44 mg (0.85–2 mg) for IBF. Total 131 FF and 15 IBF were examined in the study, with 88 FFs and nine IBFs being analyzed specifically at 6 months after the surgery. FF and IBF reported by surgeons A and B at 6 months were 97.7% vs. 91.9% FF, respectively (κ=0.95) and 100% vs. 100% IBF, respectively (κ=1). Two patients underwent longitudinal follow-up CT at 12 months, and the FF rates reported by surgeons A and B were 100% vs. 95.8%, respectively (κ=0.96). Five out of nine facet (56%) non-unions were identified at the cross-links. The remaining four facet pseudarthrosis were noted at 1–2 spinal levels caudal to the cross-links. At the final clinical follow-up, there was no rod breakage, deformity progression, neurological deficit, or symptom recurrence. The Oswestry Disability Index improved by an average of 32.8±6.3, while the mental component summary of the 36-item Short-Form Health Survey improved by an average of 4.7±2.1, and physical component summary improved by an average of 10.5±2.1. Conclusions: To our knowledge, this is the first study to report a CT that defined 92%–98% FF and 100% IBF using the lowest reported dose of RhBMP-2 in multilevel ASD surgery. The use of ultra-low dose RhBMP-2 reduces the RhBMP-2 related complications and healthcare costs.

Numerical study of conjugate heat transfer of steam and air in high aspect ratio rectangular ribbed cooling channel

Tieyu Gao,Jiangnan Zhu,Changwei Liu,Jiamin Xu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.3

The relationship between flow field and heat transfer in an air/steam cooled ribbed channel was numerically investigated and compared. The width to height ratio was 4 and the rib height to hydraulic diameter was 0.078. The conjugate heat transfer method was adopted and a uniform heat source was located in the solid domain to simulate the actual heating method in the experiment. The GGI method was used to deal with the solid-fluid interface. The fluid field structure was shown by vortex core technology. We found that the wall heat flux distribution is similar with that of the Nusselt number, which is periodic. The temperature difference of a certain position on the inner and outer wall was less than 2 K. The Nusselt number reached its peak value at No.15-18 part and then decreased. The large width to height ratio led to strong interaction between the main flow fluid and the fluid in near wall region. As a result, an extra main flow secondary flow and two separation vortexes could be observed. These three additional vortexes were all in main flow region. The two separation vortexes approached to each other in flow direction and mixed into one vortex at low Reynolds number. When Reynolds number is larger than 30000, the two vortexes remain independent. The relative distance between them reaches the minimum value and the Nusselt number reaches the peak value at the same time. In addition, the flow field structure is mainly determined by Reynolds number and the fluid type cannot obviously influence the secondary flow distribution. The generation and separation of secondary flow as well as the mixing of secondary flows can enhance the local heat transfer strength.

Unique self-assembly behavior of a triblock copolymer and fabrication of catalytically active gold nanoparticle/polymer thin films at the liquid/liquid interface

Shang, Ke,Geng, Yuanyuan,Xu, Xingtao,Wang, Changwei,Lee, Yong-Ill,Hao, Jingcheng,Liu, Hong-Guo Elsevier 2014 Materials chemistry and physics Vol.146 No.1

Methylthio-functionalized Porous Covalent Triazine Frameworks for Selective Mercury Removal from Aqueous Solution

Liangchun LI,Zhenlian YANG,Yangyi GU,Changwei LIU 대한환경공학회 2019 대한환경공학회 학술발표논문집 Vol.2019 No.-