Urban Education in Europe: Section Editors'Introduction

The Effect of Binary Solvents on Adsorption of Poly(vinylpyrrolidone) on Titanium Dioxide and Graphite Particles

“…On the other hand, in mer. Also, these behaviors have been indicated by several other experimental techniques (16)(17)(18). Further, it is interthe ethanol/hexane binary solvents, the stabilization is imparted by the adsorbed layer of PVP on titanium dioxide esting to note that the P values become large as the polarity of the binary solvents decreases.…”

Analysis of interfacial phenomena of aqueous solutions of polyethylene oxide and polyethylene glycol flowing in hydrophilic and hydrophobic capillary viscometers

“…(16b) is very similar to Eq. (15), only having the sign difference. It was found that the data of the parameter k listed in Table 1 for PEO and PEG aqueous solutions in the glass viscometer are all less than 0.016, which means that it is feasible to use Eq.…”

“…Up to now the method of combination of the literature-reported Mark-Houwink equation and the measured intrinsic viscosity under the same experimental conditions (same temperature and solvent or added salt aqueous solution) for evaluating the molar mass of polymers has been widely used for its convenience and economy [3,4]. However, adsorption phenomena frequently occur in viscosity measurements, due to the existence of hydroxyl groups on the inner surfaces of glass capillaries, which interferes with viscosity determination and leads to the usual occurrence of viscosity abnormalities, especially in the extremely dilute concentration region [5][6][7][8][9][10][11][12][13][14][15][16][17][18], and making invalid the usual method of linear extrapolation to zero concentration to obtain intrinsic viscosity.…”

“…It was found that different interfacial behavior occurred for aqueous solutions of PEO and PEG in hydrophobic and hydrophilic capillary viscometers, and furthermore, the experimental facts testify the reasonableness of the adsorption concept in explaining viscosity abnormalities in the usual viscosity measurements. The concept was first proposed in the 1950s [13][14][15] and consolidated by our group in the 1990s [5][6][7][8].…”

Effect of concentration reduction due to adsorption on the reduced viscosity of polymer solution in extremely dilute concentration regime

“…Recently great attention has been paid to the viscosity anomalies of polymer solution down to the extremely dilute concentration region [9][10][11][12][13][14][15][16][17][18]. These experimental results [19][20][21][22][23][24][25][26][27] proves that the adsorption of polymer chain onto glass capillary surface leads to the up-bending of reduced viscosity versus concentration plot occurred in the extremely dilute concentration regime due to existence of hydroxyl group on the glass surface. For describing such interfacial phenomena, the present authors have developed a quantitative expression which could successfully explain the up-bending and down-bending curves at the extremely dilute concentration [2,3,[8][9][10].…”