Synthesis of cationic N‐[3‐(dimethylamino)propyl]methacrylamide brushes on silicon wafer via surface‐initiated RAFT polymerization

Abstract

Surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization of N-[3-(dimethylamino)propyl]methacrylamide (DMAPMA) on the silicon wafer was conducted in attempt to create controllable cationic polymer films. The RAFT agent-immobilized substrate was prepared by the silanization of hydroxyl groups on silicon wafer with 3-aminopropylthriethoxysilane (APTS) and by the amide reaction of amine groups of APTS with ester groups of 4-cyano-4-((thiobenzoyl) sulfanyl) pentanoic succinimide ester (CPSE); followed by the RAFT polymerization of DMAPMA using a ''free'' RAFT agent, that is, 4-cyanopentanoic acid dithiobenzoate (CPAD) and an initiator, that is, 4,4 0 -azobis-4-cyanopentanoic acid (CPA). The formation of homogeneous tethered poly(N-[3-(dimethylamino)propyl]methacrylamide) [poly(DMAPMA)] brushes, whose thick-ness can be tuned by reaction time varying, is evidenced by using the combination of grazing angle attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and water contactangle measurements. The calculation of grafting parameters from the number-average molecular weight, M n (g/mol) and ellipsometric thickness, h (nm) values indicated the synthesis of densely grafted poly(DMAPMA) films and allowed us to predict a polymerization time for forming a ''brush-like'' conformation for the chains.

RAFT-mediated synthesis of cationic poly[(ar-vinylbenzyl)trimethylammonium chloride] brushes for quantitative DNA immobilization

“…The immobilization of CPAD onto the allylamine layer was also confirmed by the appearance of a S 2p peak curve fitted to two components with binding energies at about 162.5 eV (C-S) and 161.4 eV (C_S). The thickness of the Si\NH 2 and Si-CPAD layers were measured by ellipsometry to be 0.6±0.3 nm and 1.7 ±0.5 nm, respectively, these values are consistent with literature data [12]. The surface morphologies of the Si\H substrate after allylamine and CPAD immobilizations are shown in Fig.…”

“…RAFT-mediated polymerization of VBTAC from the RAFT agent-immobilized silicon surface was accomplished in the presence of CPAD as a free RAFT agent. It has been reported that the addition of free RAFT agent is required to render the system heterogeneous and slow down the reaction activity [12]. Moreover, introduction of free RAFT agent allows for formation of polymer in solution.…”

“…Reversible addition-fragmentation chain transfer (RAFT) polymerization is well known as a popular technique for constructing well-defining polymer structures owing to its broad monomer versatility and good control over molecular weight and polydispersity of the polymer [9][10][11]. In particular, RAFT-mediated polymerization from the solid surface immobilized chain transfer agent has been widely used to synthesize polymer brushes with a range of functionalities by virtue of the fact that end-groups remain active at the end of the polymerization [12]. For silicon substrates, the substrate-RAFT agent linkage (Si\C bond) is generally robust enough for both sustaining the reaction conditions required for RAFT-mediated polymerization and subsequent polymer brush formation and characterization.…”

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia and the associated lung neuroendocrine tumors

“…Hence, the utilization of S‐RAFT for the preparation of well‐defined polymer brushes on planar substrates has not been extensively investigated in comparison with other CRP techniques. Nevertheless, the inherent versatility and functional group tolerance of the S‐RAFT process are attractive and have recently been exploited by Advincula and coworkers17 and Caykara and coworkers 18. They reported the synthesis of polymer brushes grafted from electropolymerized polythiophene RAFT agent surfaces and cationic N ‐[3‐(dimethylamino)propyl]methacrylamide brushes on silicon substrate.…”

Surface modification of electrospun cellulose acetate nanofibers via RAFT polymerization for DNA adsorption

“…Several LRP techniques have been reported for preparation polymer functionalized surfaces, such as nitroxide-mediated radical polymerization (Bian & Cunningham, 2006;Cimen & Caykara, 2012), atom transfer radical polymerization (Bai, Zhang, Cheng, & Zhu, 2012;Bian & Cunningham, 2006;Turan, Demirci, & Caykara, 2010), reversible addition-fragmentation chain transfer (RAFT) polymerization (Demirci & Caykara, 2012;Gurbuz, Demirci, Yavuz, & Caykara, 2011;Jiang & Xu, 2013) and single-electron transferliving radical polymerization (Demirci, Kinali-Demirci, & Caykara, 2013;Percec et al, 2006). LRP provides excellent control over the molecular weight and polydispersity of graft polymers (Braunecker & Matyjaszewski, 2007;Dietrich et al, 2010).…”