Block Copolymer Self Assembly during Rapid Solvent Evaporation: Insights into Cylinder Growth and Stability

Paradiso, Sean; Delaney, Kris T.; Garcı́a-Cervera, Carlos J.; Ceniceros, Héctor D.; Fredrickson, Glenn H.

doi:10.1021/mz400572r

Cited by 89 publications

(153 citation statements)

References 26 publications

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“…It is attributed to the slight selectivity of CHX to the PB domains. The structures during drying are different from the ones during swelling at the same degrees of swelling, which points to non-equilibrium states, possibly due to a concentration gradient during solvent evaporation for the structure formation [34,35,37]. We note that solvent uptake has been found to proceed by, among others, rapid filling of existing voids by the solvent, i.e.…”

Section: Time-resolved Behavior Of the Thin Film During Svamentioning

confidence: 79%

Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing – An in-situ time-resolved GISAXS study

Sepe

Zhang

Perlich

et al. 2016

European Polymer Journal

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a b s t r a c tSolvent vapor annealing (SVA) is frequently used to improve the ordering in diblock copolymer thin films. An important question is which SVA protocol should be chosen to ensure thermodynamic equilibrium. Here, we investigate two thin films from a low molar-mass, lamellae-forming polystyrene-block-polybutadiene (PS-b-PB) diblock copolymer (28.0 kg/mol). The films are prepared by spin-coating Si wafers from toluene solutions and have film thicknesses of 215 nm and 332 nm. The as-prepared films have mainly the parallel lamellar orientation with a lamellar thickness D lam,par significantly lower than in the bulk. SVA cycles were carried out with cyclohexane, and the structural changes were followed in-situ using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). Before and after SVA, D lam,par is significantly lower than in the bulk, i.e. the equilibrium value of D lam,par in thin film geometry is different from the bulk value. Whereas the behavior of D lam,par is different for the two films in the early stages of the first swelling, it is very similar in the late stages of swelling and during drying. During the first drying, the lamellae deswell, initially slowly and later, when PS becomes glassy again, affinely. During the second SVA cycle on the thin film, the scaling behavior of the lamellar thickness is identical to the one during the first drying and to the drying behavior of the thicker film. We conclude that one cycle of solvent vapor treatment with a degree of swelling of ca. 1.5 is sufficient to bring the PS-b-PB thin films studied into equilibrium and to create a nearly defect-free lamellar structure.

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Section: Time-resolved Behavior Of the Thin Film During Svamentioning

confidence: 79%

Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing – An in-situ time-resolved GISAXS study

Sepe

Zhang

Perlich

et al. 2016

European Polymer Journal

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“…The experiments are based on ternary solutions consisting of aluminium chlorohydrate (ACH; 50 wt% hydrated dialuminum chloride pentahydroxide aqueous solution, Summit Research Laboratories Inc.), glycerol (Sigma-Aldrich), and deionised water (obtained from a Milli-Q source), which act as model systems for an important class of personal care products, namely anti-perspirants [14]. Typical drying rates for these systems are relatively slow, of the order of 1 µm·min −1 , commensurate with a range of paint-drying, dip-coating, and other drying processes [64,65,66,67]. For drying processes of considerably higher rates (∼100 µm·min −1 ), a nonlinear expression for the solvent flux J might be required, as discussed in Section S2 of the Supplementary Material.…”

Section: Model Validation With Experimentsmentioning

confidence: 99%

A minimal model for solvent evaporation and absorption in thin films

Hennessy

Ferretti

Cabral

et al. 2017

Journal of Colloid and Interface Science

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We present a minimal model of solvent evaporation and absorption in thin films consisting of a volatile solvent and nonvolatile solutes. An asymptotic analysis yields expressions that facilitate the extraction of physically significant model parameters from experimental data, namely the mass transfer coefficient and composition-dependent diffusivity. The model can be used to predict the dynamics of drying and film formation, as well as sorption/desorption, over a wide range of experimental conditions. A state diagram is used to understand the experimental conditions that lead to the formation of a solute-rich layer, or "skin", at the evaporating surface during drying. In the case of solvent absorption, the model captures the existence of a saturation front that propagates from the film surface towards the substrate. The theoretical results are found to be in excellent agreement with data produced from dynamic vapour sorption experiments of ternary mixtures comprising an aluminum salt, glycerol, and water. Moreover, the model should be generally applicable to a variety of practical contexts, from paints and coatings, to personal care, packaging, and electronics.

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“…In Figure 5, we first obtain spherical micelles with AB and AC occupying the shell and core regions, respectively (a AB = 37.04 and a AC = 30), then a AC is increased to 60 to study the morphological evolution of the micelles. In experiments, such a property variation of copolymers can be accomplished by changing solution conditions 5,27 . Our simulations show that if the initial micelle has an incomplete AB shell (ϕAB < 13%), the increased segregation force of AC at a AC = 60 will drive them to the micelle surface through the notch on AB shell, thus the relative location of AB and AC is reversed.…”

Section: Cooperative Self-assembly Of Binary Ab/ac Systemsmentioning

confidence: 99%

“…Computer simulations can more efficiently scan large parameter spaces and guide experimental efforts to promising areas. Amphiphilic block copolymers of two or more chemically distinct polymer blocks are an important class of self-organizing molecules and can be used as templating materials for nanodevices since they self-assemble into a variety of organized aggregates, which include, e.g., spherical [1][2][3][4] , cylindrical [5][6][7][8] , vesicular [9][10][11] and helical 12,13 nanoobjects. The parameters which govern the morphologies of these aggregates include the stretching degree of the core-forming blocks, the micelle/solvent interfacial tension and the repulsive interactions among corona-forming chains [14][15][16] .…”

mentioning

confidence: 99%

Controllable multicompartment morphologies from cooperative self-assembly of copolymer–copolymer blends

Wang

Sun

et al. 2017

Soft Matter

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Multicompartment nanostructures, such as microcapsules with clearly separated shell and core, are not easily accessible by conventional block copolymer self-assembly. We assess a versatile computational strategy through cooperative assembly of diblock copolymer blends to generate spherical and cylindrical compartmentalized micelles with intricate structures and morphologies. The co-assembly strategy combines the advantages of polymer blending and incompatibility-induced phase separation. Following this strategy, various nanoassemblies of pure AB, binary AB/AC and ternary AB/AC/AD systems such as compartmentalized micelles with sponge-like, Janus, capsule-like and onion-like morphologies can be obtained. The formation and structural adjustment of microcapsule micelles, in which the shell or core can be occupied by either pure or mixed diblock copolymers, were explored. The mechanism involving the separation of shell and core copolymers is attributed to the stretching force differences of copolymers which drive the arrangement of different copolymers in a pathway to minimize the total interfacial energy. Moreover, by adjusting block interactions, an efficient approach is exhibited for regulating the shell or core composition and morphology in microcapsule micelles, such as the transition from the "pure shell/mixed core" morphology to the "mixed shell/pure core" morphology in the AB/AC/AD micelle. This mesoscale simulation study identifies the key factors governing co-assembly of diblock copolymer blends and provides bottom-up insights towards the design and optimization of new a † Electronic Supplementary Information (ESI) available.

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Block Copolymer Self Assembly during Rapid Solvent Evaporation: Insights into Cylinder Growth and Stability

Cited by 89 publications

References 26 publications

Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing – An in-situ time-resolved GISAXS study

Toward an equilibrium structure in lamellar diblock copolymer thin films using solvent vapor annealing – An in-situ time-resolved GISAXS study

A minimal model for solvent evaporation and absorption in thin films

Controllable multicompartment morphologies from cooperative self-assembly of copolymer–copolymer blends

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