Poly(allylamine) plasma polymer coatings for an efficient retention of Ni(II) ions by ultrafiltration membranes

Abstract

Functional ultrafiltration membranes can be used for water decontamination. Here, we investigate the use of plasma polymerization to modify polymeric membranes with poly(allylamine) in order to filtrate aqueous solutions contaminated with Ni(II) ions. A preliminary study is performed to control growth kinetics of polymer thin films with respect to the energy provided to the precursor during deposition. Filtration experiments then enable to quantify the efficiency of the different functional coatings as for their retention of Ni(II) ions and to identify the optimal characteristics of the polymer thin films. Retention rate as high as 96% can be achieved by this single‐step functionalization process, which is very competitive compared to conventional multi‐step wet chemical functionalization techniques.

Unique combination of spatial and temporal control of maleic anhydride plasma polymerization

“…This second approach, formulated by Hegemann et al, [ 5 ] takes into account geometrical parameters of the reactor such as plasma expansion and corresponding absorbed power. They proposed to follow the evolution of the deposition rate of the plasma polymer at various specific energies to have access to one or more apparent activation energies ( E a ) related to a specific state of the precursor, using a modified Arrhenius approach as shown in the following equation [ 7,25,40–42 ] : with R as the deposition rate of the plasma polymer, F as the precursor flow rate, G as a factor depending on the operational conditions of the reactor, E a as the apparent activation energy corresponding to a given state of the precursor, and W as the average energy delivered by the generator. From Equation (), an Arrhenius‐type plot depicting ln ( R / F ) as a function of the inverse of the specific energy given to the system ( W / F ) −1 can be used to identify different polymerization regimes.…”

“…[ 19,20 ] Despite these controversial discussions, various authors have agreed on the fact that the polymerization mechanisms can be significantly modified by changing the operating mode of plasma polymerization from continuous to pulsed. [ 21–25 ] Pulsed plasma polymerization is characterized by the duty cycle (DC), defined as t on /( t on + t off ), with t on being the time when the radiofrequency (RF) excitation is supplied to the electrodes and t off being the time during which it is interrupted. A low duty cycle promotes the retention of chemical functions because it limits the fragmentation of the precursor to short time periods.…”

When chemistry of the substrate drastically controls morphogenesis of plasma polymer thin films

“…First, the growth kinetics of the poly(maleic anhydride) thin films has been studied on SiO 2 , Si–OH, and Si–CH 3 substrates using the well‐known macroscopic approach to describe plasma polymerization. [ 44–47 ] Then, the properties of the plasma polymer thin films have been characterized in the near‐surface region of the coating as well as in the bulk of the coatings. Finally, a focus has been made on the characterization of the plasma polymer growth during the early stages of polymerization.…”

“…Different regimes can be distinguished. [ 45,46 ] A steady deposition rate can be found at very low energies, which is accompanied by a low value of the activation energy (i.e., homogeneous growth regime). At this low level of input energy, the opening of the double bond of vinyl monomers (occurring close to 3 eV) is assumed to be at the origin of the main polymerization mechanism, which allows to conserve the precursor structure, with the contribution of the ions being considered as negligible.…”

Plasma activation mechanisms governed by specific energy input: Potential and perspectives

“…[5] Meanwhile, this approach was demonstrated to be applicable for many different monomers, that is, polymerizable molecules, yielding plasma polymerization. [6][7][8][9][10][11] Moreover, the concept also comprises the use of power modulation by applying on/ off pulses to reduce the average power input in the plasma aiming to enhance the structural retention of monomers. [12,13] Likewise, replacing temperature by SEI following an Arrhenius-like form might be useful for plasma conversion, plasma catalysis, and plasma jet sintering [14][15][16] -though this is still a debated subject.…”