Methyl Methacrylate Block Copolymers Research Articles

20 Years of polyolefin HPLC: Accomplishments and challenges

The first publication on the interaction of polyolefins with stationary phases for high performance liquid chromatography at high temperatures (HT-HPLC) appeared in 2003. After the successful application of temperature rising elution fractionation and the introduction of crystallization fractionation for the analysis of polyolefins with regard to chemical composition this was a step towards methods for chemical composition analysis that are not based on crystallizability of the polyolefin. Polyolefins as semicrystalline polymers comprise crystallizable and amorphous components, and HT-HPLC opened the way to separate all sample components irrespective of their crystallizability. The first application of this new approach was the separation of ethylene–methyl methacrylate block copolymers, presented in 2005. The development of the first commercial HT-HPLC instrument and the discovery of graphitic materials as efficient stationary phases for HT-HPLC were further important milestones in the development of advanced separation techniques for complex polyolefins. The ultimate goal of comprehensively analyzing complex polyolefins by composition and molar mass was achieved by high temperature two-dimensional chromatography, which is based on the online coupling of HT-HPLC and HT-SEC. Further important developments include HT-HPLC using temperature gradients and the combination of solvent and temperature gradients. In this review, the most important developments in the field over the last 20 years are discussed, and different techniques, experimental protocols and some major applications are presented. In conclusion, challenges for future developments are outlined.

Cationic β‐Scission of C−H and C−C Bonds for Selective Dimerization and Subsequent Sulfur‐Free RAFT Polymerization of α‐Methylstyrene and Isobutylene

AbstractA series of exo‐olefin compounds ((CH3)2C(PhY)−CH2C(=CH2)PhY) were prepared by selective cationic dimerization of α‐methylstyrene (αMS) derivatives (CH2=C(CH3)PhY) with p‐toluenesulfonic acid (TsOH) via β‐C−H scission. They were subsequently used as reversible chain transfer agents for sulfur‐free cationic RAFT polymerization of αMS via β‐C−C scission in the presence of Lewis acid catalysts such as SnCl4. In particular, exo‐olefin compounds with electron‐donating substituents, such as a 4‐MeO group (Y) on the aromatic ring, worked as efficient cationic RAFT agents for αMS to produce poly(αMS) with controlled molecular weights and exo‐olefin terminals. Other exo‐olefin compounds (R−CH2C(=CH2)(4‐MeOPh)) with various R groups were prepared by different methods to examine the effects of R groups on the cationic RAFT polymerization. A sulfur‐free cationic RAFT polymerization also proceeded for isobutylene (IB) with the exo‐olefin αMS dimer ((CH3)2C(Ph)−CH2C(=CH2)Ph). Furthermore, telechelic poly(IB) with exo‐olefins at both terminals was obtained with a bifunctional RAFT agent containing two exo‐olefins. Finally, block copolymers of αMS and methyl methacrylate (MMA) were prepared via mechanistic transformation from cationic to radical RAFT polymerization using exo‐olefin terminals containing 4‐MeOPh groups as common sulfur‐free RAFT groups for both cationic and radical polymerizations.

Cationic β-Scission of C-H and C--C Bonds for Selective Dimerization and Subsequent Sulfur-Free RAFT Polymerization of α-Methylstyrene and Isobutylene.

A series of exo-olefin compounds ((CH3)2C(PhY)-CH2C(=CH2)PhY) were prepared by selective cationic dimerization of α-methylstyrene (αMS) derivatives (CH2=C(CH3)PhY) with p-toluenesulfonic acid (TsOH) via β-C-H scision. They were subsequently used as reversible chain transfer agents for sulfur-free cationic RAFT polymerization of αMS via β-C-C scission in the presence of Lewis acid catalysts such as SnCl4. In particular, exo-olefin compounds with electron-donating substituents, such as a 4-MeO group (Y) on the aromatic ring, worked as efficient cationic RAFT agents for αMS to produce poly(αMS) with controlled molecular weights and exo-olefin terminals. Other exo-olefin compounds (R-CH2C(=CH2)(4-MeOPh)) with various R groups were prepared by different methods to examine the effects of R groups on the cationic RAFT polymerization. A sulfur-free cationic RAFT polymerization also proceeded for isobutylene (IB) with the exo-olefin αMS dimer ((CH3)2C(Ph)-CH2C(=CH2)Ph). Furthermore, telechelic poly(IB) with exo-olefins at both terminals was obtained with a bifunctional RAFT agent containing two exo-olefins. Finally, block copolymers of αMS and MMA were prepared via mechanistic transformation from cationic to radical RAFT polymerization using exo-olefin terminals containing 4-MeOPh groups as common sulfur-free RAFT groups for both cationic and radical polymerizations.

Self-Assembly of Polymer-Modified FePt Magnetic Nanoparticles and Block Copolymers.

The fabrication of nanocomposites containing magnetic nanoparticles is gaining interest as a model for application in small electronic devices. The self-assembly of block copolymers (BCPs) makes these materials ideal for use as a soft matrix to support the structural ordering of the nanoparticles. In this work, a high-molecular-weight polystyrene-b-poly(methyl methacrylate) block copolymer (PS-b-PMMA) was synthesized through anionic polymerization. The influence of the addition of different ratios of PMMA-coated FePt nanoparticles (NPs) on the self-assembled morphology was investigated using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). The self-assembly of the NPs inside the PMMA phase at low particle concentrations was analyzed statistically, and the negative effect of higher particle ratios on the lamellar BCP morphology became visible. The placement of the NPs inside the PMMA phase was also compared to theoretical descriptions. The magnetic addressability of the FePt nanoparticles inside the nanocomposite films was finally analyzed using bimodal magnetic force microscopy and proved the magnetic nature of the nanoparticles inside the microphase-separated BCP films.

Dewetting Behavior of Random Copolymer Films Induced by Solvent Vapor Annealing.

In recent years, the dewetting behavior of block copolymer films has been studied a lot, but that of random copolymer films was rarely studied. In this study, effects of film thickness and solvent vapor annealing duration (0 s-24 h) on the dewetting behavior of the spin-coated poly(styrene-co-acrylonitrile) (SAN) random copolymer films were mainly investigated by atomic force microscopy and contact angle method for the first time. The film thicknesses of the SAN films prepared at different concentrations were characterized by X-ray reflectometry to be 6-34 nm. With the annealing of acetone vapor, the SAN films first appear holes and then rupture into droplets which fuse and break periodically. The periodic evolutions of the droplets are due to the preferred affinity of acetone molecules with the AN segments and the change of surface energy. This phenomenon is different from the single evolutions in the spin-coated polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) block copolymer films. This illustrates the interactions between AN segments and the substrate are stronger than those between PMMA segments and the substrate in the spin-coated films.

Raspberry-like Aggregate Formation of π-Stacked Block Copolymer of Dibenzofulvene and Methyl Methacrylate Synthesized by Atom-transfer Radical Polymerization

Block copolymerization of dibenzofulvene (DBF) forming a sequence having π-stacked conformation and methyl methacrylate (MMA) forming a flexible sequence was conducted by atom-transfer radical polymerization (ATRP) where MMA was polymerized first and DBF was then blocked. The block copolymer contained a fraction with number-averaged molar mass of 873400 (vs. polystyrene) which was found to be raspberry-like aggregates with sizes of hundreds of nanometers composed of smaller spherical particles with sizes of a few to low tens of nanometers. The aggregates are considered to have a core-shell structure where strong inter-chain interaction between poly(DBF) segments form the core and flexible poly(MMA) segments are the shell, and the formation appeared to be thermally driven. The aggregates having a rigid structure stabilized the π-stacked conformation of poly(DBF) segments both in the ground state and in excited states as found by NMR and fluorescence spectra, respectively, and restricted molecular motion of both the poly(DBF) segments and poly(MMA) segments.

Synergistic toughening of poly(lactic acid) by poly(butylene adipate‐co‐terephthalate) and poly(methyl methacrylate)–poly(butyl acrylate)–poly(methyl methacrylate) block copolymer

AbstractPoly(butyleneadipate‐co‐terephthalate) (PBAT) was used to toughen poly(lactic acid) (PLA) with the addition of poly(methyl methacrylate)–poly(butyl acrylate)–poly(methyl methacrylate) (MAM) through melt blending. The impact toughness and tensile toughness of the PLA/PBAT/MAM ternary blends were greatly enhanced when the MAM content was higher than 5%. For PLA/PBAT/MAM (80/15/5) blend, the notched impact strength was as high as 42.4 kJ/m2, and the elongation at break reached 194.7%. The structure–property relationship of the PLA/PBAT/MAM ternary blends were studied through scanning electron microscopy, dynamic mechanical analysis, and contact angle measurements. It is found MAM and PBAT have a synergistic toughening effect on PLA, the MAM acts as not only a compatibilizer but also a toughening agent, which can improve the compatibility and enhance the interfacial adhesion between PLA and PBAT. As a result, the overall mechanical properties of PLA blends were improved significantly. This result provides a simple to operate and more efficient method for PLA toughening.

Block Copolymer Modified Nanonetwork Epoxy Resin for Superior Energy Dissipation.

Herein, this work aims to fabricate well-ordered nanonetwork epoxy resin modified with poly(butyl acrylate)-b-poly(methyl methacrylate) (PBA-b-PMMA) block copolymer (BCP) for enhanced energy dissipation using a self-assembled diblock copolymer of polystyrene-b-poly(dimethylsiloxane) (PS-b-PDMS) with gyroid and diamond structures as templates. A systematic study of mechanical properties using nanoindentation of epoxy resin with gyroid- and diamond-structures after modification revealed significant enhancement in energy dissipation, with the values of 0.36 ± 0.02 nJ (gyroid) and 0.43 ± 0.03 nJ (diamond), respectively, when compared to intrinsic epoxy resin (approximately 0.02 ± 0.002 nJ) with brittle characteristics. This enhanced property is attributed to the synergic effect of the deliberate structure with well-ordered nanonetwork texture and the toughening of BCP-based modifiers at the molecular level. In addition to the deliberate structural effect from the nanonetwork texture, the BCP modifier composed of epoxy-philic hard segment and epoxy-phobic soft segment led to dispersed soft-segment domains in the nanonetwork-structured epoxy matrix with superior interfacial strength for the enhancement of applied energy dissipation.

Characterizing surface porosity of porous membranes via contact angle measurements

This investigation attempts to establish and verify a novel method for quantifying surface porosity of porous polymeric membranes via contact angle measurements. Herein, we fabricate a series of porous membranes via nonsolvent induced phase separation (NIPS) comprising different concentrations of polyvinylidene fluoride (PVDF) and PVDF-poly (methyl methacrylate) block co-polymer (PVDF-PMMA) with different concentrations of water and isopropyl alcohol (IPA) in the coagulation bath. Both sessile drop and captive bubble contact angle measurements are used to determine contact angles (and porosity) for both dry and wet membranes, respectively. The former method is probably applicable for membrane distillation, aeration and de-aeration where liquid water does not saturate the membrane, whereas the latter may be more indicative of pressure-driven aqueous membrane separations where the membrane is saturated through its cross-section. Image analysis of scanning electron microscope (SEM) images quantified dry membrane surface porosity. We propose a simple analytical model to obtain wet and dry membrane surface porosity from contact angle measurements. Our results suggest that the surface porosity calculated from both wet and dry contact angle data correlates strongly with the surface porosity calculated from SEM values. However, wet contact angles of the membranes with high porosities produce significantly higher porosity values, which also establishes the importance of porous membrane swelling in determining membrane porosity for aqueous membrane separations.

Synthesis of Poly2-Hydroxyethyl Methacrylate Photo Initiated by N,N-Diethyldithiocarbamato-(1,2)-Propanediol

Photopolymerisation of 2-Hydroxyethyl methacrylate (HEMA) through the use of N,N-Diethyldithiocarbamato-(1,2)-propanediol (DCPD) was studied. The photoinitiator DCPD was synthesized from sodium N,N-Diethyldithiocarbamate (NaSR) and 3-chloro-1,2-propanediol. For the photochemical decomposition of the C – S bond, UV light at 254 nm is used. The role of the monomer concentration, reaction time and DCPD to HEMA mol ratio on the conversion of HEMA to PHEMA were studied in this paper. It was found that percentage conversion of HEMA increased both with the rise in concentration of monomer and reaction time. Further, living radical nature of the poly2-Hydroxyethyl methacrylate (PHEMA) was ascertained by the photo block copolymerization of methyl methacrylate (MMA) with PHEMA to form PHEMA-b-PMMA. The PHEMA and PHEMA-b-PMMA were characterized by FTIR, 1H-NMR, Thermogravimetry.

In-depth probing of thermally-driven phase separation behavior of lamella-forming PS-b-PMMA films by infrared nanoscopy

A non-invasive, image-based analytic method utilizing scattering-type scanning near-field optical microscopy (s-SNOM) is suggested to evaluate the phase separation behavior of lamella-forming polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) block copolymer films. Taking advantage of the penetrability of the tip-enhanced IR signal into the films, the spatio-spectral maps of each component are constructed. Subsequently, the effect of a sole and combinatorial applications of the self-assembly procedures, such as solvent vapor annealing (SVA) and/or thermal annealing (TA), on the spatial distribution of PS or PMMA components is quantitatively assessed in terms of the areal portions of the PS domain, PMMA domain, and the mixed zone that is adjacent to the domain border. Additionally, by statistically comparing the local concentration profiles, the chemical contrast between the domains turns out to be dependent upon the annealing procedures (namely, SVA and SVA + TA). This technique can pave the way to an uncomplicated but precise investigation of the polymer nanostructure-based thin film devices whose performances are critically governed by the spatial arrangement of the chemical elements.

Block copolymer binders with hard and soft segments for scalable fabrication of sulfide‐based all‐solid‐state batteries

AbstractSulfide‐based all‐solid‐state batteries (ASSBs) have attracted much attention owing to their superior safety and potentially high‐energy density. Nevertheless, sulfide‐based ASSBs suffer from limited performance in terms of their cycle life and rate capability, which is closely related to interfacial degradation during cycling. Another weakness is the absence of manufacturing protocols. Having noted that the binder can play a pivotal role in both the cell performance and scale‐up, here, we report poly(1,2‐butadiene)‐b‐poly(methyl methacrylate) (PBD‐b‐PMMA) block copolymers as the binders. At the optimal ratio, the soft PBD segments and hard PMMA segments work synergistically to strengthen adhesion among particles in the electrode and introduce elasticity in the binder network, enabling the key battery performance indicators to be improved markedly. The systematic study also reveals the importance of the microscopic distributions of these two segments. This study signifies the appropriate combination of adhesion and elasticity in designing binders for sulfide‐based ASSBs.

Porous Carbon Nanofiber-Modified Carbon Fiber Microelectrodes for Dopamine Detection.

We present a method to modify carbon-fiber microelectrodes (CFME) with porous carbon nanofibers (PCFs) to improve detection and to investigate the impact of porous geometry for dopamine detection with fast-scan cyclic voltammetry (FSCV). PCFs were fabricated by electrospinning, carbonizing, and pyrolyzing poly(acrylonitrile)-b-poly(methyl methacrylate) (PAN-b-PMMA) block copolymer nanofiber frameworks. Commonly, porous nanofibers are used for energy storage applications, but we present an application of these materials for biosensing which has not been previously studied. This modification impacted the topology and enhanced redox cycling at the surface. PCF modifications increased the oxidative current for dopamine 2.0 ± 0.1-fold (n = 33) with significant increases in detection sensitivity. PCF are known to have more edge plane sites which we speculate lead to the two-fold increase in electroactive surface area. Capacitive current changes were negligible providing evidence that improvements in detection are due to faradaic processes at the electrode. The ΔEp for dopamine decreased significantly at modified CFMEs. Only a 2.2 ± 2.2 % change in dopamine current was observed after repeated measurements and only 10.5 ± 2.8% after 4 hours demonstrating the stability of the modification over time. We show significant improvements in norepinephrine, ascorbic acid, adenosine, serotonin, and hydrogen peroxide detection. Lastly, we demonstrate that the modified electrodes can detect endogenous, unstimulated release of dopamine in living slices of rat striatum. Overall, we provide evidence that porous nanostructures significantly improve neurochemical detection with FSCV and echo the necessity for investigating the extent to which geometry impacts electrochemical detection.

Polyethylene glycol-based RAFT agent cum ATRP macroinitiator initiated block copolymerization of methyl methacrylate

PMMA-b-PEG-b-PMMA block copolymer has been synthesized by the activators regenerated by electron transfer atom transfer radical polymerization (ARGET-ATRP) of methyl methacrylate (MMA) using modified polyethylene glycol (PEG) as initiator. PEG is chemically modified by CS2 followed by an esterification to incorporate initiating sites for ATRP as well as for RAFT polymerization. The prepared macroinitiator has been characterized by FT-IR and NMR analyses for its structural validation. FT-IR and NMR analyses confirmed the successful synthesis of the macro initiator. This macro initiator has been used to prepare ABA type triblock copolymer with MMA via ARGET-ATRP. The polymerization reaction is carried out using cupric bromide (CuBr2) as catalyst in combination with N,N,N′,N″,N″-pentamethyl diethylenetriamine (PMDETA) as ligand in N, N dimethyl formamide (DMF) at 70C. Ascorbic acid is used as reducing agent. The conversion of the monomer was calculated gravimetrically. The successful preparation of the block copolymer is confirmed by FT-IR, 1H NMR and 13C NMR analyses. The MALDI-TOF mass analysis of the block copolymers also confirm the presence of monomer MMA, dithionate and PEG parts in the block copolymer. The purified block copolymer is analyzed by TGA, and SEM analyses. TGA analysis shows that the prepared block copolymer has better (Tmax = 366C) thermal stability than the PMMA (Tmax = 349C) homopolymer.

The self-assembly and thermoresponsivity of poly(isoprene-b-methyl methacrylate) copolymers in non-polar solvents

The self-assembly of a series of polyisoprene-block-poly(methyl methacrylate) (PI-b-PMMA) block copolymers, in aliphatic hydrocarbon solvents is reported for the first time. The block copolymers were prepared by a change of mechanism polymerisation (CHOMP) whereby living anionic polymerisation was used to prepare polyisoprene macroinitiators for ATRP (PI-Br), which was in turn used to polymerize MMA. The use of anionic polymerisation ensured optimal control over the molar mass and dispersity of the polyisoprene block, in a synthesis that is readily scaled-up, to enable the production of homologous series of block copolymers by varying only the molar mass of the PMMA block. The block copolymers were subsequently dispersed in n-decane or n-hexane, a selective solvent for the PI block, at high solids content of up to 30 wt%. Analysis of the resulting self-assembled nanostructures using DLS and TEM revealed that the block copolymers self-assemble into varying morphologies (spherical micelles, wormlike micelles or vesicles), dependent upon the molar mass and composition of the block copolymer, enabling the construction of a series of “phase-diagrams”. The resultant self-assembled structures were also found to be thermally responsive and, in some cases, underwent a change in morphology upon heating.

Biomimetic hierarchical porous carbon fibers via block copolymer self-assembly

Materials with well-defined porous structures, high conductivity and surface area are promising candidates in energy storage, oil absorption and catalysis applications. This work demonstrates, for the very first time, a new facile route to prepare carbon fibers exhibiting hierarchical porous designs that mimic deep-sea sponges. The fibres were prepared via wet spinning method using poly (acrylonitrile)-block-poly (methyl methacrylate) (ANMMA) block copolymers. The hierarchical porous morphologies were formed in carbon fibers due to the combined effect of self-assembly and solvent/non-solvent induced phase separation during the coagulation process. Continuous and interconnected macroporous features were observed in fibers with abundant small-sized nanopores and the fiber surface area was calculated to be 499 m2/g. Electrochemical analyses showed that the fibers possess a specific capacitance of 130 F/g at 10 A/g with excellent cyclic stability of 97% capacitance retention after 10,000 cycles. The porous fibers also exhibited excellent sorption properties with a range of organic solvents and oil, demonstrating high absorbent potential for oil/chemical clean-up. The absorption capacities were in the range of 70–92 g/g for different types of organic solvents and oil. This study paves the way towards a new class of porous carbon materials with nature mimicking designs for multifunctional applications.

Study of plasma etching impact on chemoepitaxy directed self-assembly

Directed self-assembly (DSA) of block copolymers is one of the most promising solutions investigated to obtain small and dense patterns for the sub-10 nm nodes. One of the most important aspects of the DSA technology is the orientation control of the block copolymer, which is determined by surface properties and different guiding techniques. Regarding the Arkema-CEA (ACE) chemoepitaxy process, one of the critical parameters is the preservation of the neutral layer’s properties during hydrofluoric acid wet etching, especially regarding its adherence to the titanium nitride (TiN) hard mask. In this paper, the different etching steps involved in the ACE integration flow are evaluated. Their effects on the surface properties of the TiN hard mask and on the adherence of the neutral layer are investigated by x-ray photoelectron spectroscopy and contact angle measurements. Finally, the results obtained are used to optimize the different etching steps, thus demonstrating the chemoepitaxy of a polystyrene-b-poly(methyl methacrylate) block copolymer with 32 nm pitch without alignment defects on a 100 μm2 surface.

A comparative study on the rheological, thermal, and mechanical performance of epoxy resin modified with thermoplastics

Thermoplastics and functional polymers are commonly used modifiers for epoxy (EP) resin. In this study, an EP system was fabricated and modified with methyl methacrylate block copolymer (BMG), polyphenylene oxide (PPO) and polysulfone (PSF). This was carried out to study the influence of thermoplastic polymers and functional polymers on the properties of EP resins, and the performance of the different modified EP systems was studied and compared. The curing reaction, rheological performances, heat resistance, and mechanical properties of the EP blends were investigated. Curing process of EP resin was determined as 110 °C for 1 h and 150 °C for 3 h by using non-isothermal differential scanning calorimetry (DSC) method. The rheological test revealed that the EP/BMG and EP/PPO blends exhibited low viscosity and wide processing window compared to the EP/PSF blend, thereby indicating good processing performance. The thermal stability of the modified EP blends was evaluated by using dynamic mechanical analysis methods. The results showed that the glass transition temperature (Tg ) of EP/BMG, EP/PPO and EP/PSF blends were 123 °C, 129 °C, and 131 °C, respectively. BMG showed an excellent toughening effect on EP resin compared to PPO and PSF. In addition, the flexural strength and impact strength of EP/BMG were 114 MPa and 21.2 kJ/m2, respectively. The influence of polymers on the properties of EP resin stems from their molecular structures.

Tailored inclusion of semiconductor nanoparticles in nanoporous polystyrene-block-polymethyl methacrylate thin films

Nanoporous/nanocomposite thin films with controlled morphology at nanoscale were prepared onto transparent and conductive indium tin oxide (ITO) supports by exploiting the self-assembly of a lamellar polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) block copolymer (BCP). A perpendicular orientation of PS and PMMA lamellar nanodomains was achieved by grafting a random PS-r-PMMA copolymer to the ITO supports and successive thermal annealing. Stable and reproducible nanoporous morphologies, characterized by PS lamellar nanodomains of width equal to ≈20 nm alternating to nanochannels of width equal to ≈8 nm, were obtained by irradiating the samples with an appropriate UV-C dose able to fix the relative arrangement of PS domains through activation of cross-linking reactions and selective removal of PMMA blocks. Nanoporous hybrid composites with a stable morphology were obtained either by applying the UV irradiation protocol to BCP nanocomposites characterized by selective inclusion of zinc oxide (ZnO) nanoparticles (NPs) in the PS domains (nanocomposite first/nanopores after) or by selective infiltration of cadmium selenide (CdSe) NPs in the nanochannels left free by PMMA removal through UV irradiation (nanopores first/nanocomposite after), demonstrating the strenght of the approach.

Computer simulations on double hydrophobic PS-b-PMMA porous membrane by non-solvent induced phase separation

The formation of porous membrane of double hydrophobic Polystyrene-b-Poly (methyl methacrylate) (PS-b-PMMA) block copolymer is studied by dissipative particle dynamics (DPD) simulations with the non-solvent induced phase separation (NIPS) method. It is also the first time to investigate the mechanism for double hydrophobic copolymer to form porous membrane. Results show that polymer concentration has the most significant effect on the membrane morphology. Different polymer concentrations lead to diversified morphologies. For the double hydrophobic PS-b-PMMA system, although PS and PMMA are both hydrophobic, due to their relative difference in hydrophobicity, the polymer and non-solvent undergo micro-phase separation. Channel membrane could be observed among the polymer concentration range of 30~40%. The block ratio influences the distribution of PS and PMMA block; meanwhile, block ratio has certain effect on the pore size. Effects of two different good solvents, dimethylacetamide (DMAC) and tetrahydrofuran (THF), on the membrane morphologies are also studied, the results exhibit that the block copolymer PS25-b-PMMA25 dissolved in both DMAC and THF could form channel pore, but the pore size is bigger for the DMAC system.