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Showing papers on "Glass transition published in 2002"


Journal ArticleDOI
01 Jul 2002-Polymer
TL;DR: In this paper, an electrospinning method was used to fabricate bioabsorbable amorphous poly( d, l -lactic acid) (PDLA) and semi-crystalline poly( l-lactic acids) (PLLA) nanofiber non-woven membranes for biomedical applications.

1,779 citations


Journal ArticleDOI
TL;DR: In this article, a new indicator of glass-forming ability (GFA) for bulk metallic glasses (BMGs) is proposed based on crystallization processes during cooling and reheating of the supercooled liquid.

1,121 citations


Journal ArticleDOI
TL;DR: C. Angell was born in Canberra, Australia, and studied chemistry and metallurgy at the University of Melbourne, and is focusing on the annealing behavior of hyperquenched liquids and solutions, particularly denatured protein solutions, with a sideline on nanoporous network glasses as gas storage media.
Abstract: In a review of the present title, the first requirement is to ensure that the title words are understood. While the term “glass” is broadly familiar, and the origin of the “glass transition” in terms of the crossing of system and experimental time scales is generally agreed upon, there are at least three different definitions of the material property “glass transition temperature” (Tg) in current use.1,2 Furthermore, these may differ from each other by as much as 50 K in certain higher Tg cases. The difference is a consequence of the magnitude of the “glass transformation range” within which the Tg is variously defined. This magnitude, the “width of the glass transition”, can vary greatly from system to system, for reasons discussed below. Since the quantity Tg will recur frequently in this review, it is necessary to deal adequately with the definition problem, and this will be done by reference to Figures 1 and 2 below. Depending on the liquid in question, glass transitions may be observed occurring over an enormous range in temperature, from below 50 K to above 1500 K. The reason for this range is clearly to do with the strength of the interparticle interactions, i.e., the “bonds” that are being broken as the particles rearrange. However, the reason that some glass transitions are “sharp” (meaning narrow glass transformation range, or “transition width”) and others very spread out in temperature is not so clear. It is largely to do with the “fragility” of the glassformer, but may C. A. Angell was born in Canberra, Australia, and studied chemistry and metallurgy at the University of Melbourne. After working on molten salts with J. O’M Bockris at the University of Pennsylvania for two years, he became the Stanley Elmore Fellow at Imperial College of Science, London, where he completed his Ph.D. under the direction of John W. Tomlinson. There he was awarded the Armstrong medal for graduate research 1959− 1961. He returned to Australia as lecturer in chemical metallurgy but after two years came back to the U.S. as a post-doc with Dieter Gruen at Argonne National Laboratory. In 1966, he joined Purdue University as Assistant Professor, becoming full Professor in 1971. In 1989, he moved to Arizona State University where he is now Regents’ Professor of Chemistry and Biochemistry. He has enjoyed and profited from sabbatical leaves at the University of Amsterdam, the Australian National University, Institute Laue-Langevin, Grenoble, the Ecole de Physique et Chemie Industrielle, Paris, University of Rennes-Beaulieu, Sydney University, and the University of Rome. His research interests range from rechargeable lithium batteries and fuel cells, through the phenomenology of the glass transition and the origin of fragility in liquids, to the anomalous properties of water and geochemical fluids and their relation to polyamorphism. Currently, he is focusing on the annealing behavior of hyperquenched liquids and solutions, particularly denatured protein solutions, with a sideline on nanoporous network glasses as gas storage media. 2627 Chem. Rev. 2002, 102, 2627−2650

563 citations


Journal ArticleDOI
TL;DR: While the density and solid-liquid phase transition properties are similar for both series, the new RTILs present a considerably lower viscosity and an increased ability to dissolve HgCl(2) and LaCl(3) (up to 16 times higher).
Abstract: A new series [CnOm mim][X] of imidazolium cation-based room temperature ionic liquids (RTILs), with ether and alcohol functional groups on the alkyl side-chain has been prepared. Some physical properties of these RTILs were measured, namely solubility in common solvents, viscosity and density. The solubility of LiCl, HgCl2 and LaCl3 in room temperature ionic liquids was also determined. The features of the solid–liquid phase transition were analysed, namely the glass transition temperature and the heat capacity jump associated with the transition from the non-equilibrium glass to the metastable supercooled liquid. These properties were compared with those reported for the 1-n-alkyl-3-methylimidazolium [Cn mim][X] series. While the density and solid–liquid phase transition properties are similar for both series, the new RTILs present a considerably lower viscosity and an increased ability to dissolve HgCl2 and LaCl3 (up to 16 times higher).

504 citations


Journal ArticleDOI
TL;DR: In this article, composites of fumed silica with various surface treatments and matrices of poly(vinyl acetate) of different molecular weights as well as a copolymer matrix of vinyl acetate and vinyl alcohol are reported.
Abstract: Nonlinear viscoelastic properties are reported for composites of fumed silica with various surface treatments and matrices of poly(vinyl acetate) of different molecular weights as well as a copolymer matrix of vinyl acetate and vinyl alcohol. Data above the glass transition temperature are reported here. The increase in the composite storage and loss moduli measured at low strains, and their relative rates of decrease with strain, are found to depend on filler surface treatment. The nonlinear behavior of the loss factor with strain is dramatically altered by filler treatment and quite revealing as to the likely mechanism causing the nonlinearity. In addition, the relative reinforcement and the degree of nonlinearity are found to be the highest for the lowest molecular weight matrices. The effect of copolymer substitution for the homopolymer matrix is equivalent to an increase in molecular weight. The primary underlying mechanism for reinforcement and nonlinear behavior appears to be the filler−matrix inte...

494 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of the polymer/nanoparticle interactions, surface-to-volume ratio, and boundary conditions on both the structure and dynamics of a bead-spring polymer melt surrounding a nanoscopic particle was explored.
Abstract: We perform molecular dynamics simulations of a bead−spring polymer melt surrounding a nanoscopic particle. We explore the effect of the polymer/nanoparticle interactions, surface-to-volume ratio, and boundary conditions on both the structure and dynamics of the polymer melt. We find that the chains near the nanoparticle surface are elongated and flattened and that this effect is independent of the interaction for the range of interactions we study. We show that the glass transition temperature Tg of the melt can be shifted to either higher or lower temperatures by tuning the interactions between polymer and nanoparticle. A gradual change of the polymer dynamics approaching the nanoparticle surface causes the change in the glass transition. The magnitude of the shift is exaggerated by increasing fraction of surface monomers in the system. These behaviors support a “many-layer”-based interpretation of the dynamics. Our findings appear applicable to systems in which surface interactions dominate, including b...

472 citations


Journal ArticleDOI
01 Jun 2002-Polymer
TL;DR: In this article, a First Law procedure is suggested which involves heating the sample between two set temperatures, T1 and T2, by the requirement that the degree of crystallinity of the sample should not change either with temperature or time.

460 citations


Book
10 Jul 2002
TL;DR: The world of inorganic glasses as discussed by the authors is a rich field of research in the field of glass engineering, and inorganic glass properties can be classified into three categories: glassy state, glass transition phenomenon, and glass conductivity.
Abstract: The world of inorganic glasses. The glassy state. The glass transition phenomenon. Structural techniques. Theoretical studies. D.C. conductivity. A.C. conductivity. Semiconducting glasses. Relaxation phenomena. Elastic properties and pressure effects. Optical properties. Oxide glasses. Chalcogenide glasses. Other glasses.

417 citations


Journal ArticleDOI
TL;DR: Bulk metallic glasses with a maximum thickness (tmax) of 10-27 mm were synthesized in the Fe43Cr16Mo16(C, B, P)25 system over a wide composition range by copper mold casting as discussed by the authors.

408 citations


Journal ArticleDOI
TL;DR: In this article, a specific temperature−frequency superposition law for filled elastomers is proposed, which reveals the existence of a glass transition temperature gradient in the vicinity of the particles.
Abstract: Filled elastomers exhibit a complex dependence of their viscoelastic modulus as a function of both temperature and frequency. Otherwise, recent observations on thin polymer films have shown that their glass transition temperature depends on their thickness. On the basis of these recent results and on a recent model, we propose that the mechanical behavior of the filled elastomer is strongly influenced by a gradient of the glass transition temperature in the vicinity of the particles. This allows us to suggest a specific temperature−frequency superposition law for filled rubbers. This law seems to apply very successfully on two systems with different dispersion qualities, revealing the existence of a glass transition temperature gradient in the vicinity of the particles.

392 citations


Journal ArticleDOI
TL;DR: The cage sizes and lifetimes are measured, which, respectively, shrink and grow as the glass transition approaches, and are found to be more prevalent in regions with lower concentrations and higher disorder.
Abstract: We use confocal microscopy to study particle motion in colloidal systems. Near the glass transition, motion is inhibited, as particles spend time trapped in transient "cages" formed by neighboring particles. We measure the cage sizes and lifetimes, which, respectively, shrink and grow as the glass transition approaches. Cage rearrangements are more prevalent in regions with lower concentrations and higher disorder. Neighboring rearranging particles typically move in parallel directions, although a nontrivial fraction moves in antiparallel directions, usually from particle pairs with initial separations corresponding to local maxima and minima of the pair correlation function g(r), respectively.

Journal ArticleDOI
TL;DR: In this article, Alumina/polymethylmethacrylate (PMMA) nanocomposites were synthesized using 39-nm nanoparticles and in situ free-radical polymerization.

Journal ArticleDOI
TL;DR: In this paper, a batchwise mixture of poly(lactic acid) and five plasticizers was mixed in a batch-wise mixer and then pressed into films, which were analyzed by means of dynamic mechanical analysis and differential scanning calorimetry.
Abstract: Poly(lactic acid) (PLA) was blended with five plasticizers in a batchwise mixer and pressed into films. The films were analyzed by means of dynamic mechanical analysis and differential scanning calorimetry to investigate the properties of the blends. Triacetine and tributyl citrate proved to be effective as plasticizers when blended with PLA. The glass transition temperature of PLA decreased linearly as the plasticizer content was increased. Both plasticizers were miscible with PLA to an extent of similar to 25 wt %. At this point, the PLA seemed to be saturated with plasticizer and the blends tended to phase separate when more plasticizer was added. There were also signs of phase separation occurring in samples heated at 35, 50, and 80degreesC, most likely because of the material undergoing crystallization. The presence of the plasticizers induced an increased crystallinity by enhancing the molecular mobility. (Less)

Journal ArticleDOI
TL;DR: In this paper, a composite material consisting of precipitated micron-scale Ta-rich solid solution particles distributed in a bulk metallic glass matrix was reported, where reinforcing ductile particles were precipitated during melting of the master alloy of glass-forming (Zr70Ni10Cu20)82Ta8Al10).
Abstract: We report a composite material consisting of precipitated micron-scale Ta-rich solid solution particles distributed in a bulk metallic glass matrix. The reinforcing ductile particles are precipitated during melting of the master alloy of glass-forming (Zr70Ni10Cu20)82Ta8Al10, by using previously prepared metastable Zr–Ta solid solution binary ingots. Upon cooling from the melt, the matrix undergoes a glass transition to produce an amorphous phase while the particles of precipitated Ta solid solution are distributed in the glass matrix. The resulting material not only shows high strength (∼2.1 GPa), but also has dramatically enhanced plastic strain to failure in uniaxial compression relative to single-phase bulk metallic glasses. The composite also displays limited tensile ductility.

Journal ArticleDOI
01 Mar 2002-JOM
TL;DR: Bulk amorphous metal alloys as mentioned in this paper exhibit very high strength, specific strength, and elastic strain limit, along with unusual combinations of other engineering properties, and these factors, taken together with the stability of the undercooled molten alloys with respect to crystallization have enabled studies of liquid thermodynamics, rheology, atomic diffusion, and the glass transition previously not possible in metallic systems.
Abstract: During the last two decades, researchers have developed families of metal alloys that exhibit exceptional resistance to crystallization in the undercooled liquid state. Upon cooling, these alloys readily form glass or vitrify to form bulk amorphous alloys or bulk metallic glasses. The stability of the undercooled molten alloys with respect to crystallization has enabled studies of liquid thermodynamics, rheology, atomic diffusion, and the glass transition previously not possible in metallic systems. Bulk amorphous alloys exhibit very high strength, specific strength, and elastic strain limit, along with unusual combinations of other engineering properties. These factors, taken together, suggest that bulk amorphous metals will become widely used engineering materials during the next decade.

Journal ArticleDOI
TL;DR: In this article, the authors investigated thermal expansion and diffusion properties of carbon nanotube-polyethylene composites. And they found that the addition of carbon-nanotubes to polymer matrix significantly increased the glass transition temperature.
Abstract: Classical molecular dynamics (MD) simulations employing Brenner potential for intra-nanotube interactions and van der Waals forces for polymer-nanotube interface have been used to investigate thermal expansion and diffusion characteristics of carbon nanotube-polyethylene composites. Addition of carbon nanotubes to polymer matrix is found to significantly increase the glass transition temperature Tg, and thermal expansion and diffusion coefficients in the composite above Tg. The increase has been attributed to the temperature dependent increase of the excluded volume for the polymer chains, and the findings could have implications in the composite processing, coating and painting applications.

Journal ArticleDOI
TL;DR: It is shown that introducing short-ranged attraction to a colloid suspension of nearly hard spheres by addition of a free polymer produces new glass-transition phenomena that is in qualitative agreement with recent theoretical predictions.
Abstract: Performing light scattering experiments we show that introducing short-ranged attraction to a colloid suspension of nearly hard spheres by addition of a free polymer produces new glass-transition phenomena. We observe a dramatic acceleration of the density fluctuations amounting to the melting of a colloidal glass. Upon increasing the strength of the attractions the system freezes into another nonergodic state sharing some qualitative features with gel states occurring at lower colloid packing fractions. This re-entrant glass transition is in qualitative agreement with recent theoretical predictions.

Journal ArticleDOI
TL;DR: In this article, the authors discuss the extent to which it is possible to understand and predict the behavior of frozen food products during processing and storage, on the basis of glass transition temperature values (Tg) and phenomena related to glass transition.
Abstract: Most low water content or frozen food products are partly or fully amorphous This review will discuss the extent to which it is possible to understand and predict their behavior during processing and storage, on the basis of glass transition temperature values (Tg) and phenomena related to glass transition Two main conclusions are provisionally proposed Firstly, glass transition cannot be considered as an absolute threshold for molecular mobility Transport of water and other small molecules takes place even in the glassy state at a significant rate, resulting in effective exchange of water in multi-domains foods or sensitivity to oxidation of encapsulated materials Texture properties (crispness) also appear to be greatly affected by sub-Tg relaxations and aging below Tg Secondly, glass transition is only one among the various factors controlling the kinetics of evolution of products during storage and processing For processes such as collapse, caking, crystallization, and operations like drying, extrusion, flaking, Tg data and WLF kinetics have good predictive value as regards the effects of temperature and water content On the contrary, chemical/biochemical reactions are frequently observed at temperature below Tg, albeit at a reduced rate, and WLF kinetics may be obscured by other factors

Journal ArticleDOI
TL;DR: In this paper, the authors examined the properties of aqueous solution-casted films of chitosan (C), starch-chitosans (SC), and pullulan-chitsan (PC) blends by Dynamic Mechanical Thermal Analysis (DMTA) and large deformation tensile testing.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a mechanism of viscous flow and diffusion of silicon and oxygen in silica that involves motion of SiO molecules, which is consistent with experimental measurements of silica viscosity.
Abstract: Experimental measurements of the viscosity of silica (SiO2) are critically examined; the best measurements show an activation energy of 515 kJ/mole above 1400 °C and 720 kJ/mole below this temperature. The diffusion of silicon and oxygen in silica have temperature dependencies close to that of the high temperature viscosity. Mechanisms of viscous flow and diffusion of silicon and oxygen in silica are proposed that involve motion of SiO molecules. Viscous flow is proposed to result from the motion of line defects composed of SiO molecules At temperatures below 1400 °C the fraction of SiO molecules in line defects changes with temperature. The relaxation of this fraction to an equilibrium value depends on the time. These proposed mechanisms are consistent with experimental measurements of silica viscosity.

Journal ArticleDOI
TL;DR: In this article, a calorimetric method of obtaining directly the fragility of liquids from the fictive temperatures of variably quenched glasses, is outlined, and the authors find that the most fragile liquids known are: glycerol, dibutylphthallate, 9-bromophenanthrene, salol, orthoterphenyl, propylene carbonate, decalin and its nitrogen derivative decahydroisoquinoline.
Abstract: A calorimetric method of obtaining directly the fragility of liquids from the fictive temperatures of variably quenched glasses, is outlined. “Steepness indexes” m, have been determined for a group of molecular liquids of diverse character, and vary in the range 50–150. The values obtained mostly agree well with those from earlier studies using dielectric relaxation, heat capacity spectroscopy, and viscosity data. In our method there is the advantage that the fragility is determined from the relaxation process that is basic to the calorimetric glass transition temperature measurement, namely, that of the enthalpy. The calorimetric measurements also yield the liquid and glass heat capacities, and entropies of fusion, permitting relationships between thermodynamic and kinetic responses to be examined simultaneously. We study glycerol, dibutylphthallate, 9-bromophenanthrene, salol, orthoterphenyl, propylene carbonate, decalin and its nitrogen derivative decahydroisoquinoline, and find the latter two to be the most fragile liquids known, m =145 and 128 respectively. Surprisingly, of the liquids studied, decalin has the smallest increase in heat capacity at the glass transition. By contrast, the strongest liquid, glycerol, has the largest increase. However, the thermodynamic fragility of decalin, assessed from the scaled rate of increase of the excess entropy above Tg, is found to be high, due to the unusually small value of the excess entropy at Tg. Conversely, the entropy-based fragility for glycerol is the lowest. Thus the correlation of kinetic and entropy-based thermodynamic fragilities reported in recent work is upheld by data from the present study, while the basis for any correlation with the jump in heat capacity itself is removed.

Journal ArticleDOI
01 Feb 2002-Polymer
TL;DR: In this paper, a polyurethane/Na+-montmorillonite nanocomposites were synthesized using modified 4,4′-di-phenymethylate diisocyanate (M-MDI), modified polyether polyol (MPP), and Na+-moronite (layered clay).

Journal ArticleDOI
TL;DR: It is argued that physical factors, namely residual crystal phase and specific surface area, determine the isothermal and nonisothermal crystallization behavior of ground amorphous samples as opposed to intrinsic differences in the structure of theAmorphous phase.

Journal ArticleDOI
TL;DR: In this paper, a transparent oxyfluoride glass ceramics containing LaF3 and ErF3 was prepared and the fluorescent characteristics of Er3+, such as emission spectra and lifetime of excited states were investigated.

Journal ArticleDOI
TL;DR: In this paper, the spectral and thermally spectral stability of seven fluorene-based blue-light-emitting polymers in film states was investigated, and a glass transition temperature dependence for excimer emission in the polymers was demonstrated.
Abstract: We have studied the spectral (UV−vis absorption and fluorescence) and thermally spectral stability of seven fluorene-based blue-light-emitting polymers in film states. These polymers have different side chain and backbone structure. Spiro-functionalization at the C-9 bridge position of fluorene unit could significantly improve the emission spectral quality (narrower spectrum and shorter tail extended to longer wavelength direction) and thermally spectral stability of 9,9-disubstituted polyfluorene derivatives. A glass transition temperature dependence for excimer emission in the polymers was demonstrated, and the improvement of thermally spectral stability by the spiro-functionalization is attributed to the increase of glass transition temperature. The backbone structural modification for 9,9-disubstituted polyfluorenes by alternatively inserting substituted phenylene units could provide blue emission with the spectral quality and thermally spectral stability even better than spiro-functionalized polyfluo...

Journal ArticleDOI
01 Jul 2002-Lait
TL;DR: The glass transition of amorphous lactose occurs in the vicinity of room temperature at a water content of about 6.8 g (g × 100) -1 of lactose corresponding to an equilibrium relative humidity of 37% and 0.37 a w (water activity).
Abstract: Spray-drying is a rapid dehydration method allowing production of high quality dairy powders. In dehydration and subsequent powder handling and storage, however, both chemical and physical changes, such as caking, lactose crystallisation, and nonenzymatic browning, may impair powder characteristics and result in loss of powder quality. Many of these changes are related to the physical state of lactose, as rapid removal of water in spray drying results in the formation of low- moisture, amorphous, noncrystalline structures of lactose and other milk components. The amor- phous components may exist as solid-like glasses or highly supercooled, viscous liquids. The forma- tion of amorphous, glassy lactose during spray drying allows production of a free-flowing powder. High temperatures or residual water contents at the later stages of the drying process, however, may cause stickiness, caking, browning, and adhesion of the powder particles to the processing equip- ment. The glass transition of amorphous lactose occurs in the vicinity of room temperature at a water content of about 6.8 g (g × 100) -1 of lactose corresponding to an equilibrium relative humidity of 37% and 0.37 a w (water activity). At higher water contents, as the glass transition of amorphous lactose is well below storage temperature, dairy powders become sticky and the amorphous lactose may exhibit time-dependent crystallisation. Crystallisation of amorphous lactose may also release sorbed water from the amorphous material, which enhances other deteriorative changes, such as the nonenzymatic browning reaction. Amorphous lactose in dairy powders encapsulates milk fat, which, as a result of lactose crystallisation, is released and becomes susceptible for rapid oxidation. The glass transition and water activity are, therefore, important factors controlling processability, handling properties and stability of dairy powders.

Journal ArticleDOI
TL;DR: In this article, the results were interpreted assuming progressive evolution of the random coil regions forward the more stable β-sheet conformation, as induced by the different applied preparation conditions or treatment.
Abstract: Films of silk fibroin cast from fibroin-water solutions at different casting temperatures and untreated or treated after casting with methanol, were characterized by differential scanning calorimetry (DSC), under static and dynamic mode, thermogravimetric analysis and dynamic mechanical thermal analysis. DSC revealed the presence of a lower temperature endothermic phenomenon centered at about 70 °C for the as-prepared room temperature cast film, and other typical material thermal parameters - glass transition, crystallization, and thermal degradation - more or less pronounced depending on the specific preparation procedure and thermal or solvent treatment. These results were interpreted assuming progressive evolution of the random coil regions forward the more stable β-sheet conformation, as induced by the different applied preparation conditions or treatment. The low temperature endothermic transition observed in DSC (30-120 °C) corresponded in the dynamic mechanical analysis to a quite anomalous behavior, with a sharp decrease and immediate increase of E'. Conditions producing modifications of the thermal and dynamic mechanical curves, as well as analogies with the thermogravimetric analysis findings, were analyzed and discussed.

Journal ArticleDOI
Xiaowei Zhan1, Yunqi Liu1, Xia Wu1, Shuai Wang1, Daoben Zhu1 
TL;DR: In this paper, a series of conjugated copolymers having oxadiazole, quinoline and quinoxaline moieties in the main chain based on fluorene were synthesized in good yields by palladium-catalyzed Suzuki coupling reaction, a new approach different from the traditional polyhydrazide precursor route.
Abstract: A novel series of conjugated copolymers having oxadiazole, quinoline, quinoxaline, and phenylenecyanovinylene moieties in the main chain based on fluorene were synthesized in good yields by palladium-catalyzed Suzuki coupling reaction, a new approach different from the traditional polyhydrazide precursor route (oxadiazole-containing polymers), acid-catalyzed Friedlander condensation reaction (polyquinolines), and Knoevenagel condensation polymerization (poly(phenylenecyanovinylene)). The thermal, electrochemical, and optical properties of these copolymers were examined. All these polymers possess excellent thermal stability with glass transition temperatures of 114−208 °C and onset decomposition temperatures of 387−415 °C. Cyclic voltammetry studies reveal that these copolymers possess low-lying LUMO energy levels ranging from −3.01 to −3.37 eV and low-lying HOMO energy levels ranging from −6.13 to −6.38 eV and may be promising candidates for electron-transporting or hole-blocking materials in light-emitt...

Journal ArticleDOI
TL;DR: In this article, the corrosion rates of the Fe50−xCr16Mo16C18Bx glassy alloys with a diameter of 1.2 mm were in the range of 10−3−10−2 mm−1 in 1, 6 and 12 N HCl solutions at 298 K.

Journal ArticleDOI
02 Jan 2002-Langmuir
TL;DR: In this paper, a simple method to synthesize binary polymer brushes from two incompatible polymers of different polarity was proposed, based on a subsequent step-by-step grafting of carboxyl-terminated polystyrene and poly(2-vinylpyridine) to the surface of a Si wafer functionalized with 3-glycidoxypropyl-trimethoxysilane.
Abstract: We report a simple method to synthesize binary polymer brushes from two incompatible polymers of different polarity. The synthetic route is based on a subsequent step-by-step grafting of carboxyl-terminated polystyrene and poly(2-vinylpyridine) to the surface of a Si wafer functionalized with 3-glycidoxypropyl-trimethoxysilane. The end-functional polymers were spin-coated on the substrate, and grafting was carried out at a temperature higher than the glass transition temperature of the polymers. The composition of the binary brushes can be regulated based on grafting kinetics of the first polymer by the change of time or/and temperature of grafting. This method reveals a smooth and homogeneous polymer film on the macroscopic scale, while at the nanoscopic scale the system undergoes phase segregation effecting switching/adaptive properties of the film. Upon exposure to different solvents, the film morphology reversibly switches from “ripple” to “dimple” structures as well as the surface energetic state swi...