RAFT copolymerization of acid chloride-containing monomers

Seo, M.,Hillmyer, M. Royal Society of Chemistry 2014 Polymer chemistry Vol.5 No.1

Effect of homopolymer in polymerization-induced microphase separation process

Park, Jongmin,Saba, Stacey A.,Hillmyer, Marc A.,Kang, Dong-Chang,Seo, Myungeun Elsevier 2017 Polymer Vol.126 No.-

<P><B>Abstract</B></P> <P>We report on the phase separation behaviors of polymerization mixtures containing a polylactide macro-chain transfer agent (PLA-CTA), styrene, divinylbenzene, hydroxyl-terminated PLA (PLA-OH), and a molecular chain transfer agent which enable the ability to tune the pore size of a cross-linked polymer monolith in a facile manner. Cross-linked monoliths were produced from the mixtures via reversible addition-fragmentation chain transfer (RAFT) polymerization and converted into cross-linked porous polymers by selective removal of PLA while retaining the parent morphology. We demonstrate that pore sizes are tunable over a wide range of length scales from the meso- to macroporous regimes by adjusting the ratio of PLA-CTA to PLA-OH in the reaction mixture which causes the phase separation mechanism to change from polymerization-induced microphase separation to polymerization-induced phase separation. The possibility of increasing porosity and inducing simultaneous micro- and macrophase separation was also realized by adjustments in the molar mass of PLA which enabled the synthesis of hierarchically meso- and macroporous polymers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Porous P(S-co-DVB) is derived by etching of polylactide in the precursor. </LI> <LI> Pore size is tunable from meso-to macroporous regime. </LI> <LI> Homopolymer swells domains formed by polymerization-induced microphase separation. </LI> <LI> Polymerization-induced phase separation occurs upon high loading of homopolymer. </LI> <LI> Simultaneous micro-/macrophase separation results in hierarchically porous polymer. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Olefin block copolymer thermoplastic elastomers

구종민,Frank S. Bates,Marc A. Hillmyer 한국고분자학회 2008 한국고분자학회 학술대회 연구논문 초록집 Vol.33 No.2

Interfacial Polymerization of Reactive Block Polymers for the Preparation of Composite Ultrafiltration Membranes

Seo, Myungeun,Moll, David,Silvis, Craig,Roy, Abhishek,Querelle, Sarah,Hillmyer, Marc A. American Chemical Society 2014 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.53 No.48

<P>Interfacial polymerization of an acid chloride-containing block polymer and a multivalent amine in the presence of a macroporous support was explored as a means to generate a nanoporous thin film composite (TFC) membrane potentially useful for ultrafiltration. When polylactide-<I>b</I>-poly(styrene-<I>co</I>-vinylbenzoyl chloride) (PLA-<I>b</I>-P(S-<I>co</I>-VBC)) in an organic phase and <I>m</I>-phenylenediamine (MPD) in an aqueous phase were used as the reactive block polymer and the amine, respectively, a block polymer thin film was successfully formed on a polysulfone support. This nanostructured film could be converted into a nanoporous layer by subsequent PLA etching under mild basic conditions. While most organic solvents used to dissolve PLA-<I>b</I>-P(S-<I>co</I>-VBC) damaged the support and decreased permeability of the resulting membrane, use of a mixture of methyl isobutyl ketone and acetonitrile produced a TFC membrane with high permeability.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/iecred/2014/iecred.2014.53.issue-48/ie5032259/production/images/medium/ie-2014-032259_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ie5032259'>ACS Electronic Supporting Info</A></P>

Optimization of Long-Range Order in Solvent Vapor Annealed Poly(styrene)-<i>block</i>-poly(lactide) Thin Films for Nanolithography

Baruth, A.,Seo, Myungeun,Lin, Chun Hao,Walster, Kern,Shankar, Arjun,Hillmyer, Marc A.,Leighton, C. American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.16

<P>Detailed experiments designed to optimize and understand the solvent vapor annealing of cylinder-forming poly(styrene)-<I>block</I>-poly(lactide) thin films for nanolithographic applications are reported. By combining climate-controlled solvent vapor annealing (including in situ probes of solvent concentration) with comparative small-angle X-ray scattering studies of solvent-swollen bulk polymers of identical composition, it is concluded that a narrow window of optimal solvent concentration occurs just on the ordered side of the order–disorder transition. In this window, the lateral correlation length of the hexagonally close-packed ordering, the defect density, and the cylinder orientation are simultaneously optimized, resulting in single-crystal-like ordering over 10 μm scales. The influences of polymer synthesis method, composition, molar mass, solvent vapor pressure, evaporation rate, and film thickness have all been assessed, confirming the generality of this behavior. Analogies to thermal annealing of elemental solids, in combination with an understanding of the effects of process parameters on annealing conditions, enable qualitative understanding of many of the key results and underscore the likely generality of the main conclusions. Pattern transfer via a Damascene-type approach verified the applicability for high-fidelity nanolithography, yielding large-area metal nanodot arrays with center-to-center spacing of 38 nm (diameter 19 nm). Finally, the predictive power of our findings was demonstrated by using small-angle X-ray scattering to predict optimal solvent annealing conditions for poly(styrene)-<I>block</I>-poly(lactide) films of low molar mass (18 kg mol<SUP>–1</SUP>). High-quality templates with cylinder center-to-center spacing of only 18 nm (diameter of 10 nm) were obtained. These comprehensive results have clear and important implications for optimization of pattern transfer templates and significantly advance the understanding of self-assembly in block copolymer thin films.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-16/am503199d/production/images/medium/am-2014-03199d_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am503199d'>ACS Electronic Supporting Info</A></P>

Hierarchically Porous Polymers from Hyper-cross-linked Block Polymer Precursors

Seo, Myungeun,Kim, Soobin,Oh, Jaehoon,Kim, Sun-Jung,Hillmyer, Marc A. American Chemical Society 2015 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.137 No.2

<P>We report synthesis of hierarchically porous polymers (HPPs) consisting of micropores and well-defined 3D continuous mesopores by combination of hyper-cross-linking and block polymer self-assembly. Copolymerization of 4-vinylbenzyl chloride (VBzCl) with divinylbenzene (DVB) in the presence of polylactide (PLA) macro-chain-transfer agent produced a cross-linked block polymer precursor PLA-<I>b</I>-P(VBzCl-<I>co</I>-DVB) via reversible addition–fragmentation chain transfer polymerization. A nanoscopic bicontinuous morphology containing PLA and P(VBzCl-<I>co</I>-DVB) microdomains was obtained as a result of polymerization-induced microphase separation. While a basic treatment of the precursor selectively removed PLA to yield a reticulated mesoporous polymer, hyper-cross-linking of the precursor by FeCl<SUB>3</SUB> generated micropores in the P(VBzCl-<I>co</I>-DVB) microdomain via Friedel–Crafts alkylation and simultaneously degraded PLA to produce the HPP containing micropores in the mesoporous framework. The mesopore size of the HPP could be precisely controlled from 6 to 15 nm by controlling the molar mass of PLA. We demonstrate acceleration in adsorption rate in the HPP compared to a hyper-cross-linked microporous polymer.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2015/jacsat.2015.137.issue-2/ja511581w/production/images/medium/ja-2014-11581w_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja511581w'>ACS Electronic Supporting Info</A></P>