Hydrogen-bonding induced alternating thin films of dendrimer and block copolymer micelle

Abstract

The hydrogen-bonding induced alternating multilayer thin films of dendrimers and block copolymer micelles were demonstrated. The block copolymer micelles derived from amphiphilic poly(2-ethyl-2-oxazoline)-block-poly(ε-carprolactone) (PEtOz-PCL) in aqueous phase have a core-shell structure with a mean hydrodynamic diameter of 26 nm. The hydrogen bonding between the PEtOz outer shell of micelle and the carboxyl unit of poly(amidoamine) dendrimer of generation 4.5 (PAMAM-4.5G) at pH 3 was utilized as a driving force for the layerby-layer alternating deposition. The multilayer thin film was fabricated on the poly(methyl methacrylate) (PMMA) thin film spin-coated on silicon wafer or glass substrate by the alternate dipping of PEtOz-PCL micelles and PAMAM dendrimers in aqueous solution at pH 3. The formation of multilayer thin film was characterized by using ellipsometry, UV-vis spectroscopy, and atomic force microscopy. The PEtOz outer shell of PEtOz-PCL micelle provided the pH-responsive hydrogen bonding sites with peripheral carboxylic acids of PAMAM dendrimer. The multilayer thin film was reversibly removed after dipping in aqueous solution at pH ≥ 5.6 due to dissociation of the hydrogen bonding between PEtOz shell of PEtOz-PCL micelle and peripheral carboxyl units of PAMAM dendrimer.

Advanced Organic Optoelectronic Materials: Harnessing Excited‐State Intramolecular Proton Transfer (ESIPT) Process

“…The threshold for amplifi cation was lower than 20 μ J cm − 2 pulse − 1 , indicative of easy population inversion as well as the highly effi cient dendritic effect for site-isolation (Figure 19 b). [ 90 ] Contrary to conventional laser dyes, HBT (see inset of Figure 19 c) exhibited better ASE performance at the relatively high doping levels (up to 33 wt%) in the polycarbonate (PCbisZ) fi lms. [ 89 ] The lowest ASE threshold (10 μ J cm − 2 ) and the strongest output intensity were obtained for the 26 wt% HBT doped in PC-bisZ fi lm.…”

New characterization methods for block copolymers and their phase behaviors

“…For diblock copolymers, which consist of two different polymers, the segregation of the block components due to thermodynamic incompatibility and the connectivity of the two chains yields various nano-structures such as lamellar (LAM), hexagonally packed cylinder (HEX), spheres arranged in body centered cubic lattice (BCC), double gyroid (DG) and hexagonally perforated lamellar (HPL) in bulk as well as in solution. 2,24,[30][31][32][33][34][35][36] Figure 1(a) shows an overview of the most commonly observed morphologies of diblock copolymers. 37 The morphology of the microphase-separated domains is governed by the degree of polymerization, the volume fraction of *Corresponding Author.…”

Self-doped carboxylated polyaniline: effect of hydrogen bonding on the doping of polymers

“…E-mails: Jayant_Kumar@uml.edu or Lynne_Samuelson@us.army.mil S.-C. Kim et al layer-by-layer self-assemblies, 10,11 nanotechnology, [12][13][14][15][16][17] and the detection of divalent metal ions. 18 In spite of many potential applications of carboxylated polyaniline (PCA), the chemical synthesis of this polymer has not been successful with chemical oxidative polymerization because of the poor solubility of a monomer in acidic media.…”