Water-assisted Self-assembly Fabrication Of Urushiol-based Polymer Microporous Films

In this paper, the microporous films of four urushiol-based polymers differing in polarity have been successfully fabricated by water-assisted self-assembly in the moisture atmosphere. Furthermore, several influencing factors on the formation of urushiol-based polymers microporous films and the different morphologies, such as the polymer surface free energy, the concentration of the polymer solution, the moist airflow speed, the relative humidity in the atmosphere, and the substrates, etc, were investigated.Firstly, urushiol-formaldehyde polymer (PUF) honeycomb structured films have been successfully fabricated by water-assisted self-assembly. The films were characterized by Scanning Electronic Microscopy (SEM), Atomic Force Microscope(AFM) and Energy Dispersive Spectrometer(EDS), etc. The experimental results showed that the polarity group (-OH) quantity of the surrounding pore was higher than the pore wall. With the increase of the humidity of the atmosphere, the speed of the moisture airflow, and the volume of the solution, the pore size of PUF increased. Different from other literatures which could obtain regular pores only in low concentrations, the regular pores of PUF films were formed when the concentrations ranged from 38.1 to 88.9 mg/mL. Furthermore, PUF microporous films were hydrophobic, and the PUF films retained the original morphology after being immerged in 10% hydrochloric acid or 10% NaOH for 3h.Secondly, urushiol-titanium chelate polymer (PUT) and urushiol titanium chelate polymer/multi-walled carbon nanotube composite material (PUT/CNT) microporous films have been fabricated by water-assisted self-assembly. The films were characterized by SEM, AFM, EDS and the Laser Scanning Confocal Microscope(LSCM), etc. Inverse gas chromatography (IGC) was used to test the surface properties of PUT and PUT/CNT. The experimental results indicated that the regular honeycomb PUT/CNT microporous films could be successfully prepared by water-assisted self-assembly method, but PUT could (?)ot. Meanwhile, decreased humidity and increased solution concentration leaded to reducing pore size. Moreover, PUT/CNT's surface free energy of the dispersive component and Lewis acid-base interactions were larger than that of PUT's. The Lewis acidic number K_a of PUT and PUT/CNT was 0.1853 and 0.2062, while the basic number K_b of PUT and PUT/CNT was 0.9662 and 0.6250, respectively. The PUT/CNT porous films retained the original morphology after being immerged in 10% hydrochloric acid or 10% NaOH, xylene for 24h. The PUT/CNT porous films exhibited good thermal resistance.Lastly, in the static moisture atmosphere, urushiol-formaldehyde diethylenetriamine polymer (PUFD) microporous films have been successfully fabricated by water-assisted self-assembly. The comparison of the two methods indicated PUFD microporous films with monolayer could be fabricated by spreading on water but with multilayer by spreading on solid. Furthermore, several influencing factors on the formation of the PUFD microporous films and the different morphologies, such as the molecular weight, the concentration of the polymer solution, the relative humidity in the atmosphere and the substrates, were investigated. The results showed that the water surface, as a spreading substrate, was suitable to form orderly porous films for such a polymer. To get regular structure PUFD porous film, the number average molecular weight of PUFD should exceed 4.8×10~3. The monolayer film with a relative uniform pore size distribution could be formed from the polymer with concentration of 6.0 mg/mL at the relative humidity of 90% and room temperature by using a water surface.