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Key parameters coupling with the instantaneous nucleation concept (ie, the Big Bang analogy) was used to model immersion precipitation process. The merits of the acquired model were verified via comparing its predictions with experimental results of two well-prepared and characterized cellulose acetate (CA) and polyacrylonitrile (PAN) membranes. A morphology predictable map, DPg À1 versus / 1 , was constructed, where DP, g and / 1 are osmotic pressure difference between nonsolvent and dope solution, dope viscosity and intruded nonsolvent volume fraction into the dope, respectively. The phase separation map, DPg À1 (proportional with apparent system diffusivity with the unit of time À1 ) versus / 1 showed three regimes which, at least qualitatively, depicted the correct morphological evolution trends of the studied systems. Phase sepa-ration in regime one of CA membrane with the longest delayed time or lowest DPg À1 , led to bead-like morphology. CA membrane with the shortest elapsed time or highest DPg À1 , separated to finger-like morphology in regime three. Finally, phase separation in the intermediate regime of CA membrane, ended up to sponge-like morphology. Phase separation time scales of the PAN membranes versus intruded nonsolvent into the dope solution were located in finger-like region of the CA membrane, which its downward transition lowered the fingers population.

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Ordered microporous films were fabricated via static breath figure process and in situ polymerization of ethyl cyanoacrylate (ECA) monomers. The influences of various parameters including solvent type (dichloromethane and chloroform), ECA concentration (0.2 and 1 wt%), temperature (17°C and 26°C), and substrate (glass, mica, PE, PP, and PET) were investigated on the structure of breath Figure (BF) films. Highly ordered porous films were generally formed at lower concentration of ECA and at 17°C for dichloromethane (DCM) and at 26°C for chloroform (CLF). The pores average diameter (D̅) of the films were in the range of 1 to 5 μm. The formation of regular porous structures were elucidated using the Marangoni (thermocapillary) convection flow and the rate of the polymer precipitation around the water droplets. There were an optimum ΔT (the temperature difference between the air and the solution surface) to create ordered BF film, regardless of solvent type. The prepared films have potential for templating applications.

Simpler, cheaper, and fast methods to characterize material properties are important in industrial plants. One of these properties is molecular weight which is measured generally by size exclusion chromatography, an expensive method and also limited for polyolefins which have few solvents. Melt flow index (MFI) measurement is simple, cheap, and rapid that could be a considerable method to estimate Mw of polymers. In this work, mathematical correlation between MI* (a new defined MFI), first melt dropping of blend (t 1 ), weight fraction (w i ) and Mw in binary polyethylene blends, PE/PE wax, has been investigated by using a new device. Results show that relationships MI* and t 1 with w i of the blended materials follow a modified Arrhenius equation (Wong equation) and also new non-Arrhenius equations for prediction of MI of blends have been investigated. We proposed a modified molecular weight ( Mm) for Bremner and Rudin's equation (Bremner et al., J Appl Polym Sci 1990, 41, 1617, which is used in 1/MI* and t 1 correlations with molecular weight of polymer.

Self-standing isoporous membranes based on amphiphilic block copolymers (BCPs) are an outstanding candidate for efficient separation processes. Such fascinating membranes have been generated through combining the BCP self-assembly (micro-phase separation) together with the classical non-solvent induced phase separation (macro-phase separation), known as SNIPS process. However, the controllability, reproducibility, and cost-effectiveness of the process along with the mechanism for pores generation are still challenging in the SNIPS strategy, especially when new BCP or conditions are utilized. It is mainly due to the narrow efficacy window of numerous variables influencing the desired structure formation. In this review, first, an overview of the one-step readily scalable SNIPS technique and the stepwise explanation of the process are given. Then the formation mechanism of SNIPS membranes, according to the related hypotheses and assumptions proposed on the basis of experimental evidence so far, is presented and discussed. As the main focus , governing factors in the SNIPS process which affect the preparation and structural characteristics of final membrane structures are entirely reviewed and interpreted. This review will help to have a better understanding of the connection between determinant factors and final membrane structure, which facilitates successful preparation of BCP membranes via SNIPS.