An Acid Test: Facile SI‐ARGET‐ATRP of Methacrylic Acid

Abstract

Atom transfer radical polymerization (ATRP) of methacrylic acid (MAA) is challenging. Herein is reported a study of conditions for facile surface‐initiated ATRP by activator regenerated electron transfer (SI‐ARGET‐ATRP) growth of poly‐methacrylic acid (PMAA) chains from a plasma polymer surface bearing surface‐immobilized α‐bromoisobutyryl bromide, with no deoxygenation required. Factors that affect PMAA polymer growth off the surface under ARGET‐ATRP conditions are systematically investigated, such as monomer/catalyst ratio, solvent, and, most importantly, addition of salts and change of pH. While the concentrations of the copper catalyst and acid affect grafting, the most pronounced effect arises from the concentration of chloride ions. Adding 0.1 m NaCl and acidifying the reaction solution to pH 3 offers the best trade‐off between reaction rate and reproducibility; yielding ≈60 nm thick PMAA graft polymers in 1 h under ambient conditions. Using this easily scalable recipe and surface analysis, the grafted polymers are verified to be pure PMAA and the graft coatings to be homogenous across a substrate of 100 mm diameter.

Shelf-Life Optimisation of Plasma Polymerised (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPOpp) Coatings; A New Possible Approach to Tackle Infections in Chronic Wounds

“…Previous reports for the thickness of EtOHpp under the same conditions ranged from 30–40 nm [ 33 ], which is within the range what has been achieved in this work. The same applies for the HMDSOpp adhesion layer [ 34 ].…”

“…For this work, three different plasma polymers were necessary. First, plasma polymerised Ethanol (EtOHpp), because it is suitable as a control sample by providing good adhesion for both and [ 33 ]. Second, plasma polymerised Hexamethyldisiloxane (HMDSOpp) was used as an adhesion layer for the TEMPOpp coatings to prevent delamination from the silicon substrate [ 34 , 35 ].…”

Laser-Grafted Molecularly Imprinted Polymers for the Detection of Histamine from Organocatalyzed Atom Transfer Radical Polymerization

“…Fantin et al suggested to work in an acidic environment to prevent end-group cyclization . Michl et al built on this by selecting SI-ARGET-ATRP and were able to graft poly­(methacrylic acid) (PMAA) brushes with a film thickness of ∼60 nm within 1 h reaction time . However, since recognition of targets in MIPs can greatly depend on the formation of H-bonds, this can be a troublesome solution.…”

“…35 Michl et al built on this by selecting SI-ARGET-ATRP and were able to graft poly(methacrylic acid) (PMAA) brushes with a film thickness of ∼60 nm within 1 h reaction time. 36 However, since recognition of targets in MIPs can greatly depend on the formation of H-bonds, this can be a troublesome solution. Haupt and co-workers reported the grafting of P(MAA-co-EGDMA) MIP films from SiO 2 nanoparticles and planar substrates using iridium-catalyzed photo-ATRP.…”