Poly PIPAAm

Stearoyl-terminated PIPAAms (PIPAAm-CigH35) was obtained by the reaction of the primary amino end group of PIPAAm-NH2 with a large excess of acyl chlorides [23]. A block copolymer of PIPAAm and poly(styrene) (PIPAAm-PSt) was obtained by a condensation reaction... 

A poly(propylenamine) dendrimer (11, Fig. 6.37) functionalised with poly-(N-isopropylacrylamide) (PIPAAm) (see Section 4.1.2) was used as dendritic host for anionic cobalt(II)-phthalocyanine complexes (a, b) as guests, which are held together by supramolecular (electrostatic and hydrophobic) interactions [57]. These dendritic complexes were investigated as catalysts in the above-mentioned oxidation of thiols, where they show a remarkable temperature dependence the reaction rate suddenly increases above 34°C. One attempted explanation assumes that the dendritic arms undergo phase separation and contraction above the Lower Critical Solubility Temperature (LCST). At this temperature the phthalocyanine complex site is more readily accessible for substrates and the reaction rate is therefore higher. 

RODS Poly(A-isopropylacrylamide) (PIPAAm) NIH-3T3 fibroblasts Electron beam activated polymerization of 2-carboxy-iV-isopropylacrylamide through a mask on PIPAAm (or vice versa), subsequent NHS mediated binding of peptide to carboxyl functional groups 2007 [173]... 

At the early stage of the development of the heart-on-a-chip, a PDMS microfluidic network was combined with planar electrode array to measure the extracellular potential from individual adult cardiomyocytes [54]. Another microfluidic device with an array of electrodes was developed to electrically measure the metabolic profile of cardiomyocytes and optically measure cell contractility [55]. Grosberg et al. first introduced a tissue level heart-on-a-chip to measure the contractility of neonatal cardiac muscle tissue [52]. In the design, eight muscular thin films (MTF) were fabricated on a chip. A layer of poly(N-isopropylacrylamide) (PIPAAm) dissolved at below 35 °C is spin-coated on top of a glass slide (Fig. 5A). Subsequently, a PDMS layer was coated on top of the PIPAAM layer. The PDMS layer was used to seed neonatal rat ventricular cardiomyocytes. The substrate seeded with cells is placed in the bath and the film layers were manually cut to fabricate an array of two opposite rows of four rectangular film layers of MTFs. The MTFs are peeled off after PIPAAm is dissolved as a solution when kept below 35 °C. Finally, electrodes are placed on the top and the bottom of MTFs. 

FIGURE 3.2.5 Fabrication of transplantable cocultured hepatic cell sheet, (a) Hepatocytes were selectively adhered to poly(IPAAm-BMA) cografted domains at 27°C. (b) After increasing temperature to 37°C, endothelial cells were adhered to PIPAAm domains, (c) When the temperature was changed from 37 C to 20°C, the cocultured hepatic cell sheet was recovered from the surface. Reprinted from Ref. [SO], with permission. 

For exact results while determining the intrinsic viscosity it is crucial to keep the temperature constant. In general, the accuracy of the temperature should be at least better than 0.1. In this context, it is noteworthy that the solvent viscosity as well as the viscosity of the polymer solution is always decreasing with the temperature while the intrinsic viscosity can also increase with the temperature. Figure 5.5 gives an example for aqueous solutions of poly(N-isopropyl-acrylamide) (PipAAm) and poly(acrylamide) (PAAm). The viscosity of the pure solvent water is shown as well. 

Fig. 5.5. Zero-shear viscosity qQ as a function of the temperature T for poly (acrylamide) (PAAm) and poly(A/-iso-propyl-acrylamide) (PipAAm) In aqueous solution (c=0.1 wt%).The viscosity for the solvent water as a function of the temperature Is plotted as well. Data from [77]...

The aqueous solution of PipAAm shows a decreasing intrinsic viscosity as well as a decreasing viscosity. In this case, a rising temperature leads to decreasing poly-... 

Note that in order to keep style and consistency we abbreviate poly(A -isopropylacrylamide) as PiPAAm, though other abbreviations are typically used (PNIPAM, pNIPAAm, etc.). We also use such abbreviations as Ac for acetate. Ad for adenine, A1 for alcohol, Eth for ether, Es for ester, Oz for oxazoline. 

Polymeric micelles to deliver photosensitizeis for photodynamic therapy van Nostmm CF Pluronics poly(ethylene glycol)-lipid conjugates pH-sensitive PiPAAm-based micelles polyion complex micelles dmg loading biodistribution studies therapeutic efficiency 2004 [65]... 

Poly(/V-n-propylacrylamide) PnPAAm [130, 131,218,237, 246-249] Stmctural isomer of PiPAAm... 

ND, not determined PIPAAm, poly(A -isopropylacrylamide) TRCS, temperature-responsive cell culture surfaces. Determined by ellipsometric measurement. 

Ito et al. have a used triblock copolymer, which contains hydrophobic poly[(R)-3-hy-droxybutyrate] (PHB) sandwiched between two hydrophilic PIPAAm units (PIPAAm-PHB-PIPAAm), and preparing TRCS by a coating method for expecting that hydrophobic... 

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