Star polymer-assembled thin film composite membranes with high separation performance and low fouling

Jeon, Sungkwon,Park, Chan Hyung,Park, Sang-Hee,Shin, Min Gyu,Kim, Hyun-Ji,Baek, Kyung-Youl,Chan, Edwin P.,Bang, Joona,Lee, Jung-Hyun Elsevier 2018 Journal of membrane science Vol.555 No.-

<P><B>Abstract</B></P> <P>Thin film composite (TFC) membranes have attracted intense interest due to applications in various molecular separation processes including water purification, gas separation, organic solvent separation and saline-gradient energy production. In particular, growing global demands for clean water and reduced energy consumption have raised interest in highly permselective and low fouling TFC membranes for water treatment and desalination. This drive has led to the design of new molecular structures of TFC membranes using advanced materials. Here, we designed a new building block material, a star-shaped polymer, which can be assembled into the selective layer of the TFC membrane <I>via</I> a commercial interfacial polymerization (IP) technique. This ideal 3-dimensional compact globular geometry along with high density end-functional groups enabled the realization of membranes with higher permselectivity as well as superior antifouling properties even compared to commercial membranes. We demonstrate the remarkable versatility of this building block by using the same starting materials to fabricate membranes that can function either as nanofiltration or reverse osmosis membrane depending on the IP process conditions, which is not feasible with the conventional materials used in membrane fabrication.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TFC membranes were fabricated by interfacial polymerization of star polymers (SP). </LI> <LI> RO and NF performances can be obtained by adjusting the polymerization conditions. </LI> <LI> SP assembly produces a highly permselective layer with a unique stratified structure. </LI> <LI> SP-assembled membranes show separation performance exceeding commercial membranes. </LI> <LI> SP-assembled membranes have superior fouling resistance to commercial membranes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Thin film composite reverse osmosis membranes prepared via layered interfacial polymerization

Choi, Wansuk,Jeon, Sungkwon,Kwon, Soon Jin,Park, Hosik,Park, You-In,Nam, Seung-Eun,Lee, Pyung Soo,Lee, Jong Suk,Choi, Jongmoon,Hong, Seungkwan,Chan, Edwin P.,Lee, Jung-Hyun Elsevier 2017 Journal of membrane science Vol.527 No.-

<P><B>Abstract</B></P> <P>Reverse osmosis (RO) process using a thin-film composite (TFC) membrane is a current leading technology for water desalination. The polyamide permselective layer of the TFC membrane enables salt retention and water permeation, with the ultimate goal of minimizing the permselective layer thickness for maximum energy efficiency. Yet this drive towards reducing the permselective layer thickness is greatly handicapped by the interfacial polymerization (IP) approach used to fabricate TFC membranes. We present layered interfacial polymerization (LIP) as a new paradigm for fabricating TFC membranes with unprecedented nanoscale control in the permselective layer thickness and smoothness, coupled with the advantage of industrial scale manufacturability. Membranes fabricated using LIP demonstrated high NaCl rejection necessary for water desalination, with water permeance ≈ 86% and permselectivity ≈ 450% greater than that of the membranes prepared using conventional IP and comparable water permeance and permselectivity ≈ 17% higher than that of commercial RO membranes. In addition, the unique smooth morphology of the LIP-assembled membrane surface enabled to mitigate the membrane fouling compared to the characteristic rough surface of the conventional IP-assembled membrane.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PA TFC RO membrane is fabricated via layered interfacial polymerization (LIP). </LI> <LI> LIP enables nanoscale and independent property control with process simplicity. </LI> <LI> LIP membrane has permselectivity greater than both commercial and control membranes. </LI> <LI> LIP membrane exhibits lower fouling property than the conventional control membrane. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Tailoring the Permselectivity of Water Desalination Membranes via Nanoparticle Assembly

Chan, Edwin P.,Mulhearn, William D.,Huang, Yun-Ru,Lee, Jung-Hyun,Lee, Daeyeon,Stafford, Christopher M. American Chemical Society 2014 Langmuir Vol.30 No.2

<P>Thin film composite membranes can selectively separate mono- and divalent ions from water via solution-diffusion of each species through a dense but ultrathin, highly cross-linked polymer “skin” layer; water is transported across the membrane faster than associated salts. Changing the selectivity of the “skin” layer typically requires adjusting the monomer chemistries that make up the polymer “skin” layer, but doing so also impacts a host of other membrane properties. Here, we employ electrostatic layer-by-layer deposition of inorganic nanoparticles to enhance the permselectivity of an existing commercial nanofiltration membrane. We chose this approach because it is simple and robust and does not require any change to the underlying chemistry of the thin film composite (TFC) membrane. We found that a single layer of nanoparticles was sufficient to increase the permselectivity of the membrane by nearly 50%, compared to the virgin TFC membrane. In order to understand the mechanism for permselectivity enhancement, we developed a modified solution-diffusion model to account for the additional hydraulic resistance of the nanoparticle layer, which can faithfully capture the effect of nanoparticle layer thickness on the observed water and salt flux of the modified TFC membrane.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2014/langd5.2014.30.issue-2/la403718x/production/images/medium/la-2013-03718x_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la403718x'>ACS Electronic Supporting Info</A></P>

Molecular Layer‐by‐Layer Assembled Thin‐Film Composite Membranes for Water Desalination

Gu, Joung‐,Eun,Lee, Seunghye,Stafford, Christopher M.,Lee, Jong Suk,Choi, Wansuk,Kim, Bo‐,Young,Baek, Kyung‐,Youl,Chan, Edwin P.,Chung, Jun Young,Bang, Joona,Lee, Jung‐,Hyun WILEY‐VCH Verlag 2013 ADVANCED MATERIALS Vol.25 No.34

<P><B>Molecular layer‐by‐layer (mLbL) assembled thin‐film composite membranes</B> fabricated by alternating deposition of reactive monomers on porous supports exhibit both improved salt rejection and enhanced water flux compared to traditional reverse osmosis membranes prepared by interfacial polymerization. Additionally, the well‐controlled structures achieved by mLbL deposition further lead to improved antifouling performance.</P>

Nanoscale Pillar-Enhanced Tribological Surfaces as Antifouling Membranes

Choi, Wansuk,Chan, Edwin P.,Park, Jong-Hyun,Ahn, Won-Gi,Jung, Hyun Wook,Hong, Seungkwan,Lee, Jong Suk,Han, Ji-Young,Park, Sangpil,Ko, Doo-Hyun,Lee, Jung-Hyun American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.45

<P>We present a nonconventional membrane surface modification approach that utilizes surface topography to manipulate the tribology of foulant accumulation on water desalination membranes via imprinting of submicron titanium dioxide (TiO2) pillar patterns onto the molecularly structured, flat membrane surface. This versatile approach overcomes the constraint of the conventional approach relying on interfacial polymerization that inevitably leads to the formation of ill-defined surface topography. Compared to the nonpatterned membranes, the patterned membranes showed significantly improved fouling resistance for both organic protein and bacterial foulants. The use of hydrophilic TiO2 as a pattern material increases the membrane hydrophilicity, imparting improved chemical antifouling resistance to the membrane. Fouling behavior was also interpreted in terms of the topographical effect depending on the relative size of foulants to the pattern dimension. In addition, computational fluid dynamics simulation suggests that the enhanced antifouling of the patterned membrane is attributed to the enhancement in overall and local shear stress at the fluid TiO2 pattern interface.</P>

Dynamics and Transport in Polymer Membrane

Bradley R. Frieberg,Jacob D. Tarver,Cheol Jeong,Madhusudan Tyagi,Edwin P. Chan,Christopher M. Stafford,Tsung-Han Tsai,WenXu Zhang,Bryan Coughlin,Christopher L. Soles 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2