Solvent casting method

Ogata et al. (1997) first prepared PLA/ organoclay (OMMT) blends by dissolving the polymer in hot chloroform in the presence of dimethyl distearyl ammonium modified MMT (2Ci8MMT). XRD results show that the silicate layers forming the day could not be intercalated in the PLA/MMT blends, prepared by the solvent-cast method. Thus, the clay existed in the form of tactoids, consisting several stacked silicate monolayers. 

Chen et al. (67) reported the use of trifluoroacetic acid (TFA) as a cosolvent with tetrahydrofuran (THF) to improve dispersion and processability of the nanocomposites. They prepared MWCNT-PMMA composite films with varying CNT content by solvent casting method using 10 vol % TFA as a co-solvent with tetrahydrofuran (THF). SEM and optical microscopy revealed a good dispersion of nanotubes in solvent and PMMA. The composites showed low percolation... 

ADSCs are a clinically applicable source for cell therapy. Tse et al. fabricated a PCL/PLA scaffold using the solvent-cast method, and the scaffolds were found to... 

The advantages of this sintering method, when compared to solvent casting methods used in previous studies, include (i) elimination of shrinkage, (ii) elimination of the need for potentially expensive scale-up steps such as vacuum drying, (iii) reduction of processing time (slabs have been produced in 2 h, compared to 4 days required for solvent casting), and (iv)... 

PVA, Mw 89,800-98,000 g/mol and hydrolysis degree >99%, was purchased from Sigma-Aldrich and used as received. PVA films were obtained by dissolving a known amount of PVA in water to obtain a 7.8 wt% solution under stirring. Films were prepared by the solvent casting method, by pouring the former solution into plastic Petri dishes and allowing the solvent to evaporate at 60 °C. 

B.K. Kuila and A.K. Nandi, Physical, mechanical and conductivity properties of poly(3-hexylthiophene)-montmorillonite clay nanocomposites produced by the solvent casting method. Macromolecules, 37, 8577-8584 (2004). 

The current methods of preparation of films are mainly based on solvent-casting approaches, which entail numerous disadvantages. To overcome solvent casting method limitations, HME technology was employed to prepare polymeric films. 

The solvent casting method was developed by Mikos et al. [48] amongst others for pure PLA, and several authors have used the method to manufac-... 

SBR1/PB55 and SBR2/PI55 were obtained by a solvent-cast method, using homogeneous solutions of the mixtures with toluene (17,18). Those with PP/EPR were prepared as follows (14). The mixtures were first dissolved in hot xylene. A... 

Fig, 13. Various processes encountered in the pattern formation of polymer mixtures by the solvent-casting method. The concentration of the polymers increases from the top left to the bottom right during the solvent evaporation. 

In solvent casting method an already prepared polymer is first dissolved in the appropriate solvent and then simply cast onto the surface of the electrode. After solvent evaporation, the film of polymer is formed, ft is a very simple approach, but unfortunately two disadvantages have to be considered, uniformity of the polymeric film and reproducibility of its preparation [2]. This method is usually used for the preparation of redox active or nonconducting polymers [3]. Coatings of composites of nanomaterials with polymers are also often prepared by this method [4]. 

Ultrathin polymer films can be prepared using two kinds of technology. The first includes wet processes like LB, spreading, dipping or solvent casting methods. The other is dry processing, such as physical vapour deposition (PVD) and chemical vapour deposition (CVD). Of these methods, the CVD methods, such as plasma polymerisation, are frequently used to make polymer thin films [24-26]. 

Rhim et al. (2006) compared two different methods for obtaining PLLA films, i.e. solvent casting and thermocompression. In the first case, dried PLLA pellets were dissolved in chloroform at room temperature. The solution was spread on a casting surface (made of Teflon) and allowed to dry for 24 h at room temperature. In the thermocompression process, PLLA was placed in a press formed by two plates of stainless steel lined with aluminum foil, heated to 190 °C. Then, a pressure of about 69 MPa was applied for 3 min. Using the solvent-casting method, PLLA films retained up to 10% of the solvent, which acted as a plasticizer and affected film properties. Thermocompressed film showed a greater thermal stability and better mechanical properties moreover, they did not contain residual solvent. 

The anionic exchange concept has been employed on PVA polymer electrolyte to improve the ionic conductivity of alkaline PVA-based SPE. The solvent casting method started by blending PVA and quaternary amine, such as tetraethyl ammonium chloride (TEAC) in dimethyl sulfoxide (DMSO) to form PVA/TEAC blend polymer membrane [38]. After immersed in 32 wt.% KOH solution, the alkaline PVA/TEAC SPE membranes were obtained. When more TEAC was added, the crystalline intensity of PVA fiem XRD peak was greatly reduced. It was suggested that the addition of TEAC into the PVA polymer matrix increased the domain of amorphous region and then the hydrophilicity. The XRD spectra are evidenced in Fig. 5. 

Wyttenbach et al. published a characterization scheme of amorphous film generated by solvent casting method, Screening of Polymers for Amorphous Drug Stabilization (SPADS) (Wyttenbach et al. 2013). It focuses on the evaluation of supersaturation potential, drug and polymer miscibility, and stability. In the SPADS, three assays are performed in a 2-step process. 

MiCoS shares similar pros and cons to solvent-casting methods. With parallel preparation, it is highly efficient and effective in evaluating polymer types, drug loadings and antisolvent/solvent ratio comprehensively. However, the residue solvent and antisolvent content, which are critical for amorphous stability, cannot be determined due to low amount of solid products. The kinetic solubility results can only be interpreted qualitatively rather than quantitatively, as the particle size of the miniaturized products are not tightly controlled. 

Similar materials could be obtained by an emulsification method [253]. Nematic liquid crystal is emulsified into an aqueous dispersion of a water-insoluble polymer colloid (i.e., latex paint). An emulsion is formed which contains a droplet with a diameter of a few microns. This paint emulsion is then coated onto a conductive substrate and allowed to dry. The polymer film forms around the nematic droplets. To prepare an electrooptical cell a second electrode is laminated to the PDLC film [253]. In the phase separation and solvent-casting methods the chloroform solutions of liquid crystal and polymer are also used [254, 255]. The solution is mixed with the glass spheres of the required diameter to maintain the desired gap thickness and pipetted onto a hot (140 °C) ITO-coated glass substrate [255]. After the chloroform has completely evaporated another ITO-coated glass cover is pressed onto the mixture and then it is cooled down. Structural characteristics of the PDLC films are controlled by the type of liquid crystal and polymer used, the concentration of solution, the casting solvent, the rate of solvent evaporation, perparation temperature, etc. [254]. 

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