Simple Photochemical Route to Block Copolymers via Two‐Step Sequential Type II Photoinitiation

Abstract

A simple method for the preparation of block copolymers by a two‐step sequential Type II photoinitiation is described. In the first step, amine functionalized poly(methyl methacrylate) (PMMA‐N(Et)2) is prepared by photopolymerization of methyl methacrylate at λ = 350 nm using benzophenone and triethyl amine as photosensitizer and hydrogen donor, respectively. Subsequent benzophenone‐sensitized photopolymerization of tert‐butyl acrylate using PMMA‐N(Et)2 as hydrogen donor yielded poly(methyl methacrylate)‐block‐poly(tert‐butyl acrylate). The obtained hydrophobic block copolymer is readily converted to amphiphilic polymer by hydrolysis of the tert‐butyl ester moieties of the block copolymer as demonstrated by contact angle measurements. All polymers are characterized by NMR, Fourier transform infrared and UV–vis spectroscopies, and differential scanning calorimetry (DSC) thermal analyses.

One‐Step Synthesis of Fluorescent Poly(divinylbenzene) Particles without Fluorescent Monomers

“…When irradiated, BP is excited and it is able to abstract a hydrogen from a suitable donor at its excited state. [15] Initial reactions were carried out at 2% (by volume) monomer concentration, which is typical for PP, and RhB amount is gradually decreased from 2:1 to 0.1:1 RhB: BP mole ratio, while other reaction parameters including BP to DVB mole ratio (1:100), reaction time (68 h), and total reaction volume (30 mL) were held constant. Figure 2a,b shows the photograph of the reaction vessels before (Figure 2a) and after polymerization (Figure 2b).…”

“…When irradiated, BP is excited and it is able to abstract a hydrogen from a suitable donor at its excited state. [ 15 ]…”

Polymer Brushes via Surface-Initiated Electrochemically Mediated ATRP: Role of a Sacrificial Initiator in Polymerization of Acrylates on Silicon Substrates

“…The experimental value of the water contact angle for a silicon wafer covered with hydrophilic PHEA brushes (61.9° ± 1.2 and FSE ~44.8 (± 0.3)–46.4 (±0.1) Table S6 , entry 1) was lower than that for wafers with previously attached bromine initiator (73.0° ± 1.2 and FSE ~ 42.6 (± 0.2)–44.0 (±0.1), Table S6 , entry 5). On the contrary, the chain extension by hydrophobic P t BA segment caused a significant increase in the contact angle value (up to 98.6° ± 1.4 and FSE ~ 36.5 (± 0.2)–37.2 (±0.1), Table S6 , entry 4) characteristic of hydrophobic materials [ 78 , 79 ]. The results confirm the correlations between the surface properties of the obtained polymer materials and the chemical nature of the compounds used for modification.…”

Access to Photoreactive Core‐Shell Nanomaterials by Photoinitiated Polymerization‐Induced Self‐Assembly

“…The available set of photoinduced reactions constitutes an efficient, finely controllable, and environmentally friendly toolbox in chemistry for applications as varied as light‐induced deprotection reactions in organic synthesis, photopolymerization in dentistry, 3D printing, and photocatalysis . Importantly, the use of so‐called λ‐orthogonal reactions, which can be triggered independently by suitable choice of reaction partners and irradiation wavelengths, allows complex reaction schemes and new functions in materials The incorporation of photoreactive groups in polymeric materials enables a great variety of possibilities, e. g ., collapse of single‐chain nanoparticles, block copolymer synthesis by classic free‐radical polymerization, and crosslinking reactions . The usual mild reaction conditions also enable bioconjugation onto materials such as nanoparticles (NPs) .…”