Hyperbranched Acrylate Copolymer via Initiator‐Fragment Incorporation Radical Copolymerization of Divinylbenzene and Ethyl Acrylate: Synthesis, Characterization, Hydrolysis, Dye‐Solubilization, Ag Particle‐Stabilization, and Porous Film Formation

Abstract

Summary: Soluble hyperbranched acrylate copolymers were prepared by the copolymerization of divinylbenzene (0.10 mol · L−1) and ethyl acrylate (0.50 mol · L−1) using dimethyl 2,2′‐azoisobutyrate of high concentrations (0.30–0.50 mol · L−1) as initiator at 70 and 80 °C in benzene. The copolymer formed at 80 °C for 1 h showed the weight‐average molecular weight of 2.5 × 105, the small radius of gyration of 10 nm, the low second virial coefficient of 5.7 × l0−7 mL · g−2 as shown by the MALLS measurements at 25 °C in tetrahydrofuran, and also the very low intrinsic viscosity of 0.10 dL · g−1 at 30 °C in benzene. The hyperbranched copolymer exhibited an upper critical solution temperature (35 °C on cooling) in an acetone‐water (60:11 v/v). The copolymer showed an ability to encapsulate and transfer Rhodamine 6G as a dye probe and could stabilize Ag nanoparticles. The porous film was prepared by simply casting an acetone solution of the hyperbranched copolymer on a cover glass. The copolymer molecules radially arranged on the surface layer of the spherical pores as observed by the polarized optical microscope. The hyperbranched acrylate copolymer was hydrolyzed by KOH to yield poly(carboxylic acid).Optical microscope image (crossed polarizers) of a porous film from copolymer solution in acetone.imageOptical microscope image (crossed polarizers) of a porous film from copolymer solution in acetone.

Soluble hyperbranched copolymer via initiator-fragment incorporation radical copolymerization using a trivinyl monomer

“…8, indicating that the dissolution rate was faster than the precipitation one for the copolymer. Similar phenomena were observed for other hyperbranched polymers [26,27]. This might come from the unique structure of the hyperbranched polymers.…”

“…Such an ordered arrangement of the copolymer molecules is worthy of remark because the copolymer has a broad molecular weight distribution (M w /M n Z5.8) and a not-defined structure. Such phenomena as pore formation and ordered arrangement might be characteristic of the hyperbranched polymers [27]. Fig.…”

Encapsulation Using Hyperbranched Polymers: From Research and Technologies to Emerging Applications

“…Amphiphilic nanocarriers based on hyperbranched polymers are highly customizable and can form not only “unimolecular micelles” (UMs) but also “unimolecular inverted micelles” (UIMs) . These amphiphilic nanocarriers are frequently used to encapsulate small guest molecules for therapeutic and cosmetic, as well as catalytic applications. ,,− Aspects influencing the amphiphilicity of release systems based on hyperbranched polymers will be discussed in this section.…”

“…173 These amphiphilic nanocarriers are frequently used to encapsulate small guest molecules for therapeutic and cosmetic, as well as catalytic applications. 149,161,[178][179][180] Aspects influencing the amphiphilicity of release systems based on hyperbranched polymers will be discussed in this section.…”