Polystyrene-poly Methyl Methacrylate Research Articles

Diverging Polymer Acoustic Lens Design for High-Resolution Row-Column Array Ultrasound Transducers.

Spherical diverging acoustic lenses mounted on flat 2-D row-column-addressed (RCA) ultrasound transducers have shown the potential to extend the field of view (FOV) from a rectilinear to a curvilinear volume region and, thereby, enable 3-D imaging of large organs. Such lenses are usually designed for small aperture low-frequency transducers, which have limited resolution. Moreover, they are made of off-the-shelf pieces of materials, which leaves no room for optimization. We hypothesize that acoustic lenses can be designed to fit high-resolution transducers, and they can be fabricated in a fast, cost-effective, and flexible manner using a combination of 3-D printing and casting or computer numerical control (CNC) machining techniques. These lenses should increase the FOV of the array while preserving the image quality. In this work, such lenses are made in concave, convex, and compound spherical shapes and from thermoplastics and thermosetting polymers. Polymethylpentene (TPX), polystyrene (PS), polypropylene (PP), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), and room-temperature-vulcanizing (RTV) silicone diverging lenses have been fabricated and mounted on a 128 + 128 6-MHz RCA transducer. The performances of the lenses have been assessed and compared in terms of FOV, signal-to-noise ratio (SNR), bandwidth, and potential artifacts. The largest FOV (24.0.) is obtained with a 42.64-mm radius PMMA-RTV compound lens, which maintains a decent fractional bandwidth (53%) and SNR at 6 MHz (.9.1-dB amplitude drop compared with the unlensed transducer). The simple PMMA TPX, PS, PP, PDMS, and RTV lenses provide an FOV of 12.2°, 6.3°, 8.1°, 11.7°, 0.6°, and 10.4°; a fractional bandwidth of 97%, 46%, 103%, 46%, 97%, 53%, and 49%; and an amplitude drop of -5.2, -4.4, -2.8, -15.4, -6.0, and -1.8 dB, respectively. This work demonstrates that thermoplastics are suitable materials for fabricating low-attenuation convex diverging lenses for large-aperture, high-frequency 2-D transducers. This is highly desired to achieve high-resolution volumetric imaging of large organs.

Compatibilizer effect on optical properties of immiscible PMMA/PS blends

Immıscible polymethyl methacrylate/polystyrene (PMMA/PS) mixtures with various maleic anhydride-styrene-methyl methacrylate (MAStMMA) compatibilizer ratio (0, 2, 4, 6, 8 and 10) % were obtained by solution casting. The spectral results showed that the optical constants such as refractive index (n), extinction coefficient (k) and absorption coefficient increase with increasing terpolymer compatibilizer ratio. On the other hand, the optical energy gap Eg showed an inverse trend to concerning optical constants. The lowest observed energy gap was between 8 and 10 % compatibilizer ratio.

Influence of barium titanate nanoparticles on the optical properties of (PS-PMMA) blend

We investigated the influence of barium titanate NPs on the optical characteristics of a (polystyrene-poly methyl methacrylate) blend. The solution casting technique is used to prepare (PS-PMMA) polymer blend and (PS-PMMA-BaTiO3) nanocomposites. The results indicate that as barium titanate concentrations increase, the absorbance of nanocomposites increases. The optical characteristics of (PS-PMMA-BaTiO3) nanocomposites (Coefficient of absorption, Coefficient of extinction, Index of refraction, Dielectric constant's real and imaginary components) increase as barium titanate NPs concentration increases. Gap of the energy narrows as the concentration of barium titanate nanoparticles increases.

Facile approach for largely refining phase domains of PMMA/PS blends and improving their properties during extrusion

The immiscible poly(methyl methacrylate)/polystyrene (PMMA/PS) blends with three composition ratios (80/20, 70/30, and 60/40 w/w) are prepared using water-assisted mixing extrusion (WAME). The injected high-pressure water during extrusion facilitates to significantly refine the phase domains without adding compatibilizer. Compared with the counterpart blend samples prepared without injecting water, the mean diameter of the PS droplet is decreased by approximately 50% for the PMMA/PS (80/20) sample; the co-continuous structure is obviously finer for the PMMA/PS (60/40) sample. The PS phase sizes in the PMMA/PS blends prepared by WAME in this work are smaller than those reported in relevant references. The mechanism is analyzed for promoting the phase domain refinement in the PMMA/PS blends during WAME based on high-pressure rheological tests. The phase domain refinement can improve the anti-creep property of the PMMA/PS blends, and simultaneously enhance their tensile strengths and elongations at break. This work gives a guidance for refining the phase domain of immiscible polymer blends by facilely injecting high-pressure water during extrusion instead of adding compatibilizer (e.g. block or graft copolymer, and fillers).

Mechanically reinforced polystyrene-polymethyl methacrylate copolymer-graphene and Epoxy-Graphene composites dual-coated sand proppants for hydraulic fracture operations

Herein, we report mechanically reinforced dual-coated sand proppants for hydraulic fracturing operations. The dual-coated sand proppants were prepared by sequential surface modifications. The sand particles were firstly coated with polystyrene-polymethyl methacrylate copolymer (PS-PMMA) composite with commercial graphene (CG) (first composite layer) and subsequently coated with epoxy-CG composite (second composite layer). The copolymer-CG coating onto sand particles was carried out by mixing 1:1 styrene (S) and methyl methacrylate (MMA) monomers with the initiator AIBN along with CG followed by adding the mixture to sand particles with vigorous stirring and subsequent polymerization at 70 °C. The PS-PMMA-CG coated sand particles were then mixed with epoxy resin and a cure in a ratio of 4:1 along with CG and cured at 150 °C for 5 min. Chemical, mechanical, thermal, and morphological characterizations for the composite layers and dual-coated sand proppants were investigated in detail by Fourier transform-infrared spectroscopy (FT-IR), nano-indentation, thermogravimetric (TGA), optical, and scanning electron microscopic (SEM) techniques. The FT-IR results revealed that the successful formation of PS-PMMA-CG copolymer composite and cross-linked epoxy-CG composites. The XRD results indicated that the successful surface coverage of the dual composites coating onto the sand. The optical and SEM results revealed that the roundness and sphericity of the reinforced proppant particles were greater than 0.6. Interestingly, elasticity (E), and hardness (H) of the coating shells have reached a maximum of 3.97 GPa and 0.144 GPa, respectively. The thermal stability of the (PS-PMMA-CG)-(epoxy-CG) dual composite shell has reached as high as 363 °C. Furthermore, the stress resistance of the optimized dual-coated sand proppant (Sand-(PS-PMMA-CG)-(epoxy-CG)) reached as high as 10000 psi with a fine production of <10 wt%. The mechanically reinforced dual-coated sand including the most desirable characteristics of roundness and sphericity to be greater than 0.6, high-stress resistance with excellent thermal and mechanical stabilities confirmed its great potential to be applied as successful proppants in oil and gas upstream applications.

Microwave Irradiation Synthesis and Characterization of Reduced-(Graphene Oxide-(Polystyrene-Polymethyl Methacrylate))/Silver Nanoparticle Nanocomposites and their Anti-Microbial Activity.

Herein, we report a facile process for the preparation of styrene and methyl-methacrylate copolymer nanocomposites containing reduced graphene oxide and silver nanoparticles ((R-(GO-(PS-PMMA))/AgNPs)) by using (i) microwave irradiation (MWI) to obtain R-(GO-(PS-PMMA))/AgNPs and (ii) the in situ bulk polymerization technique to produce RGO/AgNPs-(PS-PMMA). Various characterization techniques, including FT-IR, XPS, Raman spectroscopy, XRD, SEM, HR-TEM, DSC, and TGA analysis, were used to characterize the prepared nanocomposites. The Berkovich nanoindentation method was employed to determine the hardness and elastic modulus of the nanocomposites. The results showed that the MWI-produced nanocomposites were found to have enhanced morphological, structural, and thermal properties compared with those of the nanocomposites prepared by the in situ method. In addition, the antibacterial activity of the prepared nanocomposites against the E. coli HB 101 K-12 was investigated, whereby an inhibition zone of 3 mm (RGO/AgNPs-(PS-PMMA) and 27 mm (R-(GO-(PS-PMMA))/AgNPs) was achieved. This indicates that the MWI-prepared nanocomposite has stronger antibacterial activity than the in situ-prepared nanocomposite.

Thermal response of polystyrene/poly methyl methacrylate (PS/PMMA) polymeric blends

The present paper reports the investigationsto evaluate thermal behavior of polystyrene/poly methyl methacrylate (PS/PMMA) polymeric blends, prepared at different compositions through solution casting method. The glass transition temperatures have been obtained using dynamic mechanical analyzer. Simultaneous measurements of temperature dependentthermal transport properties (thermal conductivity and thermal diffusivity) have been made using Hot Disk Thermal Constants Analyzer based on transient plane source. The study reveals that blending of PS with PMMA leads to different phase morphologies corresponding to different composition range which further affects the thermal performance of respective blends.

Human Fetal Osteoblast Response on Poly(Methyl Methacrylate)/Polystyrene Demixed Thin Film Blends: Surface Chemistry Vs Topography Effects.

Recent advances in materials sciences have allowed for the development and fabrication of biomaterials that are capable of providing requisite cues to instigate cells to respond in a predictable fashion. We have developed a series of poly(methyl methacrylate)/polystyrene (PMMA/PS) polymer demixed thin films with nanotopographies ranging from nanoislands to nanopits to study the response of human fetal osteoblast cells (hFOBs). When PMMA was in excess in the blend composition, a nanoisland topography dominated, whereas a nanopit topography dominated when PS was in excess. PMMA was found to segregate to the top of the nanoisland morphology with PS preferring the substrate interface. To further ascertain the effects of surface chemistry vs topography, we plasma treated the polymer demixed films using an atmospheric pressure dielectric barrier discharge reactor to alter the surface chemistry. Our results have shown that hFOBs did not have an increased short-term cellular response on pristine polymer demixed surfaces. However, increasing the hydrophilicty/wettability of the surfaces by oxygen functionalization causes an increase in the cellular response. These results indicate that topography alone is not sufficient to induce a positive cellular response, but the underlying surface chemistry is also important in regulating cell function.

Multidetector thermal field-flow fractionation as a unique tool for the tacticity-based separation of poly(methyl methacrylate)-polystyrene block copolymer micelles

Poly(methyl methacrylate)-polystyrene (PMMA-PS) micelles with isotactic and syndiotactic coronas are prepared in acetonitrile and subjected to thermal field-flow fractionation (ThFFF) analysis at various conditions of increasing temperature gradients. It is shown for the first time that multidetector ThFFF provides comprehensive information on important micelle characteristics such as size (Dh), shape (Rg/Rh), aggregation number (Z), thermal diffusion (DT) and Soret coefficients (ST) as a function of temperature from a single injection. Moreover, it is found that micelles exhibit a unique decreasing trend in DT as a function of temperature which is independent of the tacticity of the corona and the micelle preparation method used. It is also demonstrated that ThFFF can monitor micelle to vesicle transitions as a function of temperature. In addition to ThFFF, it is found from DLS analysis that the tacticity of the corona influences the critical micelle concentration and the magnitude to which micelles expand/contract with temperature. The tacticity does not, however, influence the critical micelle temperature. Furthermore, the separation of micelles based on the tacticity of the corona highlight the unique capabilities of ThFFF.

Forced assembly by multilayer coextrusion to create oriented graphene reinforced polymer nanocomposites

A potential advantage of platelet-like nanofillers as nanocomposite reinforcements is the possibility of achieving two-dimensional stiffening through planar orientation of the platelets. The ability to achieve improved properties through in-plane orientation of the platelets is a challenge and, here, we present the first results of using forced assembly to orient graphene nanoplatelets in poly(methyl methacrylate)/polystyrene (PMMA/PS) and PMMA/PMMA multilayer films produced through multilayer coextrusion. The films exhibited a multilayer structure made of alternating layers of polymer and polymer containing graphene as evidenced by electron microscopy. Significant single layer reinforcement of 118% at a concentration of 2 wt % graphene was achieved—higher than previously reported reinforcement for randomly dispersed graphene. The large reinforcement is attributed to the planar orientation of the graphene in the individual polymer layers. Anisotropy of the stiffening was also observed and attributed to imperfect planar orientation of the graphene lateral to the extrusion flow.

Lamination of Alumina Membranes to Polymer Surfaces: Thick, Hard, Transparent, Crack-Free Alumina Films on Polymers with Excellent Adhesion

Hard and transparent alumina (Al(2)O(3)) films with thicknesses in the range of 500 nm to 5 μm were successfully formed on polymethylmethacrylate (PMMA) and polystyrene (PS) surfaces. Our process is based on a lamination of anodized aluminum membranes (AAMs) to the polymer surfaces, followed by chemical etching. Because of capillary force, molten PS and liquid PMMA precursor were successfully pulled into the nanopores (10 nm diameter) within the Al(2)O(3) layers and solidified by cooling or polymerization, respectively. Our resulting AAM-laminated surfaces exhibited excellent adhesion and surface mechanical properties similar to those of fused silica, remaining crack-free and transparent even with Al(2)O(3) thicknesses exceeding 1 μm.

INFLUENCE OF SILICA NANOPARTICLES ON THE COARSENING OF CO-CONTINUOUS PMMA/PS BLENDS DURING ANNEALING

The influence of hydrophilic SiO2 nanoparticles on the stability of co-continuous structure in poly(methyl methacrylate)/polystyrene(PMMA/PS) blends under quiescent melt annealing was investigated.It was found that the filled blends displayed broader co-continuous interval and less coarsened structure than those of unfilled blends after annealing.The result indicated that the morphological stability of co-continuous blends can be improved effectively by the addition of SiO2 nanoparticles.Rheological measurements showed that the viscosity and elasticity of filled PMMA/PS blends,which were associated with the destruction process of the co-continuous structure such as breakup or retraction,were enhanced significantly.The influence of the change in the viscoelasticity and interfacial tension of blends upon the addition of SiO2 nanoparticle was analyzed qualitatively based on two available theories describing the coarsening process of the co-continuous structure of polymer blends.It was proposed that the change in the viscoelastic properties of PMMA/PS blends instead of the interfacial tension plays a dominant role in the coarsening rate of the co-continuous structure during the quiescent annealing in melt state.

Poly(methyl methacrylate)/polystyrene composite latex particles with a novel core/shell morphology

The development of colloidal chemistry and nanotechnology make it possible to precisely control the architecture of the latex particles of submicron and micron size [1–4]. Seeded polymerization is a useful technique for the design and preparation of latex particles with desirable morphology. Recently, our group has found various internal and surface morphologies in the synthesis of composite latex particles through seeded soap-free emulsion or seeded dispersion polymerization [5–9]. The particle morphologies are tunable by exquisitely controlling the thermodynamic and kinetic factors during reaction. We report here the synthesis of poly(methyl methacrylate)/polystyrene (PMMA/PS) composite latex particles which have a novel core/shell morphology. The particles were synthesized via seeded soap-free emulsion polymerization of styrene in the presence of PMMA particles by using a water-soluble nonionic azo-initiator, 2,20-azobis[2-methylN-(2-hydroxyethyl)propionamide] (VA086). Though the seeded emulsion or soap-free emulsion polymerization of styrene with PMMA latex has been widely investigated, the use of this kind of initiator was the first time to our knowledge. The polymerization kinetics and the morphology of the resulting PMMA/PS particles was studied and compared with the case using the ionic potassium persulfate (KPS) initiator. All polymerizations were performed in a 300 mL roundbottom separated flask equipped with a nitrogen inlet, a sampling syringe and a mechanical agitator. PMMA seed latex was prepared via a standard soap-free emulsion polymerization at 70 C for 5 h using KPS as initiator. The seed latex was dialyzed against deionized water for 3 days before use. A typical seeded soap-free emulsion polymerization was as follows. Appropriate amount of PMMA seed latex, deionized water and initiator VA086 or KPS were charged into the flask and bubbled with nitrogen gas for 30 min. Then, the oxygen-free styrene monomer was added, followed by the initiation of the polymerization by immersing the flask into the water bath thermostated at 70 C. The seeded polymerization was carried out for 4 h with continuous stirring. During the polymerization, fractions of 1.5 mL were withdrawn from the reaction mixture at various time intervals. The typical recipes for the preparation of PMMA seed and PMMA/PS composite latex particles were given in Table 1. The latex particles sampled during the polymerization were analyzed using a particle size analyzer (Microtrac S3500). It was confirmed that no appreciable agglomeration and new particle formation occurred during polymerization whether VA086 or KPS was used. The measurement of these samples by Fourier transform infrared spectroscopy (FT-IR, JASCO FT/IR-8000) showed that some new absorption peaks such as those near 700 and 3026 cm appeared as compared with the IR spectrum of PMMA seed particles. These peaks could be reasonably assigned to the characteristic absorptions of aromatic C–H bending and aromatic C–H stretching vibrations. The above results suggested that PS component was successfully introduced into the PMMA seed particles. The PS content (relative to PMMA) was quantified by the absorbance ratio of the peak at 700 cm (for PS) to that at 1375 cm (CH3 bending, for PMMA), with a calibration curve obtained from mixtures of PMMA and PS latex particles. From the PS content, the monomer conversion was calculated. T. Wang S. Shi (&) F. Yang Department of Materials Science and Engineering, Shenyang Institute of Chemical Technology, Shenyang 110142, China e-mail: shan.shi@hotmail.com

Facile Approach to Patterned Binary Polymer Brush through Photolithography and Surface-Initiated Photopolymerization

Taking advantage of the photobleaching and co-initiating properties of the dendritic thioxanthone (TX) photoinitiator, we developed a general and facile approach to fabricate patterned binary polymer brushes by combining photolithography and surface-initiated photopolymerization (SIPP). The dendritic TX photoinitiator monolayer was immobilized covalently on a silicon slide surface, followed by photobleaching through a mask. The resulting slides could initiate photopolymerization of methyl methacrylate (MMA) to generate a patterned poly (methyl methacrylate) (PMMA) brush, and subsequently initiate styrene (St) in the presence of TX to obtain patterned binary poly (methyl methacrylate)-polystyrene (PMMA-PS) brushes. This general and facile method could be of use in large-scale patterned binary polymer brush fabrication.

Preparation of polymer film of micro-porous or island-like structure and its application in dye-sensitized solar cell

A polystyrene (PS) film of micro-porous or island-like structure has been prepared by spin-coating the PS–PMMA (polymethyl-methacrylate) blend on sputtered platinum electrode, followed by selectively dissolving PMMA out of the blend. The film forms either micro-porous or island-like structure depending on the blending proportion of PS to PMMA. After soaking with liquid electrolyte, this film can be utilized as gel polymer electrolyte for dye-sensitized solar cell to improve its durability because the evaporation rate of liquid electrolyte can be significantly reduced. As to the convenience of cell assembly, this polymer film can also serve as a spacer and effectively separate the photo-anode and counter electrode. In addition, we also find that the cell performance is affected significantly by the polymer blend concentration. An energy conversion efficiency of 4.58% can be obtained with 2 wt% PS–2 wt% PMMA blend proportion under AM 1.5, 1 Sun illumination.

Rheological behavior of poly(methyl methacrylate)/polystyrene (PMMA/PS) blends with the addition of PMMA-ran-PS

In this work, the dynamic behavior of poly(methyl methacrylate)/polystyrene blend to which P(S0.5-ran-MMA0.5) was added was studied. Several blend (ranging from 5 to 20 wt% of dispersed phase) and copolymer (up to 20 wt% with respect to dispersed phase) concentrations were studied. The rheological behavior of the blends was compared to Bousmina’s (Rheol Acta 38:73–83, 1999) and Palierne’s (Rheol Acta 29:204–214, 1990) generalized models. The relaxation spectra of the blends were also inferred, and the results were analyzed in light of the analysis of Jacobs et al. [J Rheol 43:1495–1509, 1999]. The relaxation spectra of the blends with smaller dispersed phase (below 10 wt%) and larger copolymer concentrations (above 0.4 wt%) showed the presence of four relaxation times, two corresponding to the blend phases, τ F , corresponding to the relaxation of the shape of the dispersed phase of the blend and $$ \tau _{\beta } $$ that can be attributed to the relaxation of Marangoni stresses tangential to the interface between the dispersed phase and matrix. The experimental values of $$\tau _{F} $$ and $$ \tau _{\beta } $$ were used to infer the interfacial tension (Γ) and the interfacial complex shear modulus (β) for the different blends, Γ decreased with increasing copolymer concentration. β decreased with increasing blend dispersed phase concentration and decreasing copolymer concentration. The predictions of Palierne’s generalized model were found to corroborate the experimental data once the values of Γ and β, found analyzing the relaxation spectra, were used in the calculations. Bousmina’s model was found to corroborate the data only for larger dispersed phase concentration.

Quantitative Chemical Mapping of Nanostructured “Onionlike” Poly(methyl methacrylate)/Polystyrene Composite Particles by Soft X-ray Microscopy

In earlier work, we have produced micrometer-sized, monodisperse, poly(methyl methacrylate)/polystyrene (PMMA/PS) composite particles having a multilayered structure. A challenge to developing applications for these multilayered particles is the quantitative, spatially resolved chemical analysis of their onionlike layered structure, where some layers are thinner than 100 nm. Scanning transmission X-ray microscopy (STXM) has a spatial resolution of better than 50 nm and sufficient chemical contrast to both observe and quantitate the composition of individual layers without staining. The results of quantitative chemical analysis of the particles and standard P(S-co-MMA) random copolymers by STXM are shown to be in good agreement with 1H NMR measurements of their average composition. Results from chemical quantification of the individual layers of the onionlike particles by STXM are reported. Analyses of samples prepared with and without embedding in epoxy are compared. Our analysis takes into account the finite spatial resolution of the STXM. The extent of intermixing between layers was estimated by comparing the measured results to those generated from an assumed instrumental response function and trial compositional structures. This analysis suggests that the individual layers are relatively pure, although small amounts of intermixing (<15%) are also consistent with the results. Possible origins of intermixed layers are indicated and ways to achieve more pure layers are suggested.

Spectroscopic characterization of micro‐phase separated blends of polystyrene/polymethyl methacrylate (PS/PMMA)

AbstractAn investigation of the miscibility behaviour in polystyrene/ polymethyl methacrylate (PS/PMMA) blends of various compositions under different evaporations protocols using Fourier transform infrared (FT‐IR) and Raman Spectroscopic techniques took place in the study. Solvent selection and evaporation rates, coupled with variations in the blend composition resulted in completely different miscibility behaviour for these systems. In particular, it was found that blends with low PMMA content result in systems that exhibit PMMA domains of less than 7 microns on average. Finally, depth profiling studies of the PMMA moiety in the PS matrix show that the distribution of the low content phase is highly affected by the solvent selection as well as the blend composition.

The characteristic properties of poly(methyl methacrylate)/polystyrene core-shell composite polymer latex

In this study, the poly(methyl methacrylate/polystyrene (PMMA/PS) core-shell composite latex was synthesized by the method of soapless seeded emulsion polymerization. The morphology of the PMMA/PS composite latex was core-shell structure, with PMMA as the core and PS as the shell. The core-shell morphology of the composite polymer latex was found to be thermally unstable. Under the effect of thermal annealing, the PS shell region first dispersed into the PMMA core region, and later separated out to the outside of the PMMA core region. This was explained on the basis of lowing interfacial tension between the PMMA and PS phases owing to the interpenetration layer. The interpenetration layer, which was located at the interface of the core and shell region, contained graft copolymer and entangled polymer chains. Both the graft copolymer and entangled polymer chains had the ability to lower the interfacial tension between the PMMA and PS phases. Also, the effect of thermal annealing on the morphology of commercial polymer/composite latex polymer blends was examined. The result showed that the core-shell composite latex had the ability to enhance the compatibility of the components of polymer blends. The compatibilizing ability of the core-shell composite latex was better than that of a random copolymer. Moreover, the effect of the amount of core-shell composite latex on the morphology of the polymer blend was investigated. The polymer blends, which contained composite latex above 50% wt, showed the morphology of a double sea-island structure. In addition, the composite latex was completely dissolved in solvent to destroy the core-shell structure and release the entangled polymer chains, and then dried to form the entangled free composite polymer. The entangled free composite polymer had the ability to enhance the compatibility of the components of the polymer blend as usual. The weight ratio 3/7 commercial polymer/entangled free composite polymer blend showed the morphology of the phase inversion structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 312–321, 2003

Effect of the supercritical CO 2 on surface structure of PMMA/PS blend thin films

The phase structure development in the surface of poly(methyl methacrylate)/polystyrene (PMMA/PS) blend thin film in the presence of supercritical carbon dioxide (SCCO 2) was studied by means of phase contrast microscopy and atomic force microscopy. The surface structures obtained after spin-coating are far from thermodynamic equilibrium. A stable surface structure, which the PS-rich phase is elevated by PMMA-rich phase, is formed after annealed in supercritical CO 2. The structure can be explained by the different aggregation of the PMMA and PS in the two interfaces: air-polymer and substrate-polymer. The different surface structures are investigated as a function of treatment pressure and temperature of supercritical CO 2. A critical phase structure transition temperature/pressure was found at an explicit pressure/temperature by adjusting the condition of the supercritical CO 2. The phase structure transition point indicates a glass transition point could be found by tuning the working condition of SCCO 2. Due to the experimental difficulties in the measurement of T g of the thin films in supercritical CO 2, this study, by observing the resulting surface structure formed in supercritical CO 2, provides us a new angle to look at the problem.