Why specific mixed solvent composition leads to appropriate film formation of composite during spin coating?

Abstract

In this paper, we explain why specific mixed solvent composition leads to appropriate film formation of composite (polymer: inorganic nanoparticle) during spin coating. As a typical case, P3HT:TiO2 film formation has been discussed by taking chloroform as good solvent for P3HT while ethanol, methanol, and 2-propanol are used as co-solvents for dispersing TiO2. Mixed solvent evaporation dynamics during film drying has been simulated to explain the experimental results. Present study can be immensely useful for selecting proper solvents and their initial ratio for blend film formation of a particular phase separation.

Low-resistance silver microparticle-HEMA-PEGDA composites for humidity sensing

“…As can be seen from table 1, it was generally necessary to add more Ag than desired in the final film. This trend has been reported and explained in previous studies [43][44][45][46]; due to the low viscosity of the monomer solution, this mixture is spun off preferentially with respect to the filler particles, resulting in coatings of higher wt% of the filler. Table 2 lists the content of PEGDA, HEMA, and Ag in each CPC solution used for DWP.…”

“…As the concentration of particles in a solution are known to vary during the spin coating process [43][44][45][46], preliminary experiments were required to determine the composition of solutions for spin coating that would result in samples with the final desired composition: 75 wt% Ag. A range of solutions were prepared, spin-coated, and crosslinked, and the content of Ag was analyzed by thermogravimetric analysis (as described in section 2.3.…”

New insights into polymer-solvent affinity in thin films

“…In polymer thin film field, solvents are used into two main steps: i) for deposition purposes such as spin coating, dip coating, solution blow spinning etc.. where a solution of polymer in a solvent is used [13], [16], [17], [18], [19], [20] ii) for film post processing such as solvent vapor annealing (SVA) where solvent molecules in vapor state go into the polymer film [15], [21], [22], [23], [24]. In the specific area of block polymer thin films, the solvent selectivity is often a key parameter in the post-processing step that drives the ordering and orientation of the morphologies formed by the block polymer self-assembly, as well as order-order (and/or order-disorder) transition when one of the block is strongly swollen [22].…”

Modifying hydrogen bonding interaction in solvent and dispersion of ZnO nanoparticles: impact on the photovoltaic performance of inverted organic solar cells

“…Chloroform which was classied as "good" solvent showed highly improved dispersion of ZnO NPs in mixing with methanol, a "bad" solvent. 30 The HSPs of the mixed solvent with optimized composition was calculated to be d D ¼ 16.8 MPa 1/2 , d P ¼ 5.9 MPa 1/2 and d H ¼ 10.7 MPa 1/2 with RED ¼ 0.22 for ZnO NPs. In addition, although both toluene and methanol were proved to be "poor" solvents for dispersion of ZnO NPs (see Table S1 in ESI †), mixture of the two components with appropriate ratio resulted in highly uniform colloidal solution of ZnO NPs.…”