Hyperbranched Poly acrylic Acid Grafts

Fig. 2 Progress of hyperbranched poly(acrylic acid) graft formation on smooth gold films as measured by ellipsometry ( ) or on polyethylene powders as measured by titration ( ) of the supported - CO2H groups...

Hyperbranched Poly(acrylic Acid) Graft Synthesis on Gold Surfaces... 

Synthesis of Hyperbranched Poly(acrylic Acid) Grafts on Polyethylene Films... 

The hyperbranched poly( acrylic acid) graft films -C02H-rich interface on polyethylene can be modified by noncovalent methods just like CO2H-rich interfaces of PAA/Au grafts. This was shown by treating deprotonated 3-PAA/PE films with cationic polyelectrolytes like poly-D-lysine, and amine terminated PAMAM dendrimers at pH 7 [31]. Equation 10 illustrates the entrapment of PAMAM dendrimers in a 3-poly(sodium acrylate)/PE film. In these cases, polyvalent entrapment of the cationic electrolyte was evidenced in the ATR-IR spectriun by the appearance of amide C = O and N - H peaks of the guest dendrimer that were not present in the host 3-poly(sodium acrylate)/PE film. 

To study the solution property of novel amphiphilic hyperbranched graft copolymer chains, we further prepared amphiphilic hyperbranched poly(acrylic acid) grafted with short polystyrene copolymer (HB-PAA- -PS) with a large hydro-phihc hyperbranched PAA core and short hydrophobic PS grafted chains. The copolymer chains with different branching degrees of PAA core were carefully prepared and well confirmed by SEC, H NMR, and FT-IR. As well, the... 

Fig. 4.15 Schematic of synthesis of amphiphilic hyperbranched poly(acrylic acid) grafted with short polystyrene copolymer chains (HB-PAA-g-PS) and their linear triblock PS-PAA-PS...

Lianwei Li, Xu Wang, Chen He, and Weidong He, Association, Emulsifying and Solubilization Properties of Amphiphilic Hyperbranched Poly(acrylic acid) Grafted with Polystyrene (HB-PAA-g-PS) , J. Polym. ScL, Polym. Chem. 2013, 52, 128. 

It has been demonstrated that hydrophobic, fluorinated, hyperbranched poly(acrylic acid) films can passivate and block electrochemical reactions on metal surfaces thus preventing surface corrosion [57]. Hyperbranched films can be synthesized on self-assembling monolayers on the metal surface via sequential grafting reactions to obtain thick and homogeneous films. 

Dermody, D.L., et al.. Chemically grafted polymeric filters for chemical sensors hyperbranched poly(acrylic acid) films incorporating beta-cyclodextrin receptors and amine-functionalized filter layers. Langmuir, 1999. 15(3) p. 885-890. Laschewsky, A., et al.. Polyelectrolyte multilayers containing photoreactive groups. Macromol Chem Phys, 1997. 198(10) p. 3239-3253. 

Fig. 14. Hyperbranched polymer grafts prepared on a mercaptoundecanoic acid (MUA) self assembled monolayer confined to a gold substrate. PAAM-c-PAA represents a random copolymer of poly(acrylamide) and poly(acrylic acid) prepared from the poly(acrylic acid) carboxylic acid groups and an amine [129]...

Scheme 2 Photolithographic process for preparing patterned hyperbranched grafts of poly(acrylic acid)...

Scheme 5 Polyvalent hydrogen bonding of a a soluble poly(N-isopropylacrylamide) to a 3-PAA/PE hyperbranched graft or b a soluble poly(acrylic acid) to a hyperbranched poly(Ar-isopropylacrylamide) graft on PE...

In a previous work, Cheng et al. [322] performed the same synthesis but without any ligand excess. The resulting macromonomer was similar to that described in Scheme 69 but with a chain-end bromine atom. This macromonomer was polymerized by the ATRP process, leading to a hyper-grafted polymer. The Mark-Houwink coefficient was 0.47, which characterized the hyperbranched structure. Hydrolysis of such a polymer led to the corresponding poly(acrylic acid). Similarly, Hua et al. [323] performed the synthesis of brushlike poly(acrylic acid). 

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