Synthesis of Well‐Defined Polymer Brushes from Silicon Wafers via Surface‐Initiated se ATRP

Abstract

Synthesis of densely grafted (co)polymer brushes, including poly(n‐butyl acrylate), poly(2‐dimethylaminoethyl methacrylate), poly(n‐butyl acrylate)‐block‐poly(tert‐butyl acrylate), and poly(2‐dimethylaminoethyl methacrylate)‐block‐poly(tert‐butyl acrylate) from silicon wafer surfaces via a simplified surface‐initiated electrochemically mediated atom transfer radical polymerization under constant potential/current conditions is reported. A sacrificial (nontethered) initiator is added to form free polymer chains in solution used to estimate the molecular weights and molecular weight distributions of chains attached to the surface. The polymers show narrow molecular weight distributions (Đ = 1.10–1.33). Water contact angle measurements and ellipsometry are used to characterize wettability and thicknesses of the modified surfaces. Grafting densities up to 0.93 nm−2 are obtained. The rate of the polymerization is controlled by applying more negative potential values, which results in an increase in the surface thickness (up to 116 nm). Finally, the poly(tert‐butyl acrylate) blocks are hydrolyzed to the poly(acrylic acid) blocks. These new, densely grafted brushes are promising candidates for applications in microelectronics, nanotechnology, tailoring of surface properties, nanopatterning, or antifouling coatings.

Synthesis of naringin‐based polymer brushes via seATRP

“…1 H NMR spectra in DMSO and CDCl 3 were measured in a Bruker Avance 500 MHz spectrometer. Monomer conversion and theoretical number‐average MW ( M n,th ) were designated by NMR . MWs and MWDs were acquired by Viscotek T60A GPC (guard, 10 5 , 10 3 , and 10 2 Å PSS columns; THF eluent, flow rate 1.00 mL/min) with PS calibration.…”

“…These polymerization methods include ring‐opening polymerization, click reaction, cationic polymerization, anionic polymerization, radical (co)polymerization, reversible addition‐fragmentation chain transfer polymerization (RAFT), nitroxide‐mediated polymerization (NMP), and atom transfer radical polymerization (ATRP), as well as combinations of different methods . Considering these techniques, macromolecular brushes can be synthesized via three main approaches: “grafting through”, “grafting onto”, or “grafting from” . Undoubtedly, “grafting from” is one of the most useful technique which involves attachment of initiator molecules to the backbone and growing of polymer chains via polymerization; therefore, macromolecular brushes with high grafting density can be prepared by using these tactics …”

“…13,[16][17][18][19][20][21][22][23][24][25][26][27][28]30,32,44 Considering these techniques, macromolecular brushes can be synthesized via three main approaches: "grafting through", 2,11,[53][54][55][56] "grafting onto", 54,[57][58][59][60][61][62] or "grafting from". 51,52,[62][63][64][65][66][67][68] Undoubtedly, "grafting from" is one of the most useful technique which involves attachment of initiator molecules to the backbone and growing of polymer chains via polymerization; therefore, macromolecular brushes with high grafting density can be prepared by using these tactics. 13 Citrus-derived flavonoid molecule such as naringin (NG) with eight terminal hydroxyl groups can be used as an efficacious solution to receive functionalized polymers.…”

Synthesis of inositol‐based star polymers through low ppm ATRP methods

“…1) using different reducing agents (organic as glucose, [60] phenols, [61] ascorbic acid, [62][63][64][65] hydrazine, [61] amines, [66,67] but also inorganic such as tin(II) 2-ethylhexanoate, [60] or zerovalent metal as Ag 0 [68,69] ) in activators regenerated by electron transfer (ARGET) approach, adding zerovalent metals (Cu 0 , Zn 0 , Mg 0 , or Fe 0 ) as supplemental activators and mild reducing agents (SARA), [70][71][72][73][74][75][76][77] and applying a reducing current as in electrochemically mediated ATRP. [11,74,[78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97] Each of these ATRP methods offers a more environmentally benign and industrially relevant alternative for synthesizing polymers compared with normal ATRP. [95] The newest low ppm ATRP method, simplified electrochemically mediated ATRP (seATRP), [11,…”

“…[11,74,[78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97] Each of these ATRP methods offers a more environmentally benign and industrially relevant alternative for synthesizing polymers compared with normal ATRP. [95] The newest low ppm ATRP method, simplified electrochemically mediated ATRP (seATRP), [11,83,86,89,91,[93][94][95][96][97] offers possibility of elimination of chemical reducing agents, and creation catalyst recycle opportunity. [98] The idea of the seATRP technique is that the activator/deactivator concentration ratio is well-controlled by electrochemistry, which is an explanation of the fast development of this method.…”