Homogenous Grafted Poly(acrylic acid) Brushes on Ultra-flat Polydimethlysiloxane (PDMS) Films by UV Irradiation

Abstract

In this paper, hydrophilic poly(acrylic acid) (PAA) brushes were evenly grafted onto ultra-flat polydimethlysiloxane (PDMS) films by UV irradiation in a benzophenone (BP)/aceton/acrylic acid solution. The grafted films remain the elasticity of PDMS, which indicates the grafting reaction takes place at the superficial surface. But water affects the grafting depth much due to the good diffusion of monomers into the film.

Simple UV-Grafting of PolyAcrylic and PolyMethacrylic Acid on Silicone Breast Implant Surfaces: Chemical and Mechanical Characterizations

“…In this way, the sample, once dried can bring surface irregularities which could explain the low apparent contact angle measurements on a surface associated with a high rate of grafting. Moreover, as observed by Velazco et al [38] and Yang et al [37] the polymer could penetrate the silicone matrix and graft inside, limiting surface effects. This hypothesis would explain the change in appearance observed macroscopically on our silicone samples (Figure 5a) and justify the high grafting rate obtained for both polymers.…”

“…Thus, grafted surfaces must be compared to a control sample to assess whether the grafting rate is notable. Both bioactive polymers have a particularly high rate due to the high reactivity of the monomer and the possible penetration of the polymer into the PDMS matrix [10,37,38]. However, the PMAc-grafted silicone grafting rate shows a high standard deviation.…”

“…The following study focuses on the grafting of bioactive polymers bearing carboxylate groups such as polyacrylic acid (PAAc) and methacrylic acid (PMAc) and their chemical and mechanical characterizations. These compounds are chosen as non-toxic, biocompatible and hydrophilic polymers [10,[36][37][38][39][40][41][42]. These bioactive polymers are also very reactive [43], they have the ability to form strong bonds with various materials and are also used as surgical adhesives [44].…”

“…At a physiological pH, PAAc and PMAc are found carrying carboxylate groups [38]. The presence of a negative charge on the surface of the material may create repulsions between a negatively charged surface and the positively charged organisms [37]. This way, carboxylated polymers have the advantage of inhibiting cell adhesion by preventing the adhesion of proteins or by modifying their surface organization [20,33,35,[45][46][47].…”

Photopatterning of PDMS Films: Challenging the Reaction between Benzophenone and Silicone Functional Groups

“…Its photoreaction with a large variety of molecules, such as alcohols [3][4][5], ketones [5] and aromatic solvents [4], has been studied extensively. In the field of silicone, it has been extensively used to promote radical grafting or polymerization of various hydrophilic monomers onto PDMS (Polydimethylsiloxane) [6], including acrylic acid [7] or N-isopropyl acrylamide [8], and more recently via controlled radical polymerization [9,10].…”