PEO, deuterated

Goldmints, L Yu, G.E. Booth, C. Smith, K.A. Hatton, T.A. Structure of (deuterated PEG) (PPO) (deuterated PEO) block copolymer micelles as determined by small angle neutron scattering. Langmuir 1999, 15, 1651-1656. 

The samples of the 96% deuterated latex were prepared by a standard surfactant-free procedure which is described fully elsewhere (13). The narrow distribution fractions of PEO were obtained from Polymer Labs (Shawbury) and were manufactured by the Toya Soda Co. The details of these samples are given in Table I. 

FIGURE 13.1 Structure factors S(QZ) of the two samples with hydrogenous (solid line) and deuterated (dashed line) PEO. The structure factors are shown on three different scales in (a), (b) and (c) for clarity. 

FIGURE 13.5 Difference pair correlation functions AG(rz) between the atomic pair correlation functions of samples with deuterated and hydrogenous PEO. In the case of the 0.1 M salt concentration (solid line), the butylammonium chains were deuterated in both samples, whereas for the 0.03 M salt concentration (dashed line), both samples contained hydrogenous counterions. The volume fraction of PEO was 4% in all cases. 

Other examples of such detailed analysis of the structure with the aid of contrast variation can be found for partially deuterated polystyrene-polyisoprene (PS-Pl) diblock copolymer micelles in decane [86, 95] Pluronic (PEO-PPO-PEO) micelles in water [96, 97] PB-PEO micelles in water [85] or PEP-PEO micelles in water [44] or in water/ DMF mixture [98]. 

PDMS polydimethylsiloxane, PE polyethylene, PVP polyfiV-vinylpyrrolidone), PEP polyfethyl-ene propylene), dPEP deuterated polyfethylene propylene), PLA polyfc.L-lactide), PEO poly (ethylene oxide)... 

The homopolymers polyethyleneimine (PEI, Mn k, 600 g/ mol) and chitosan Mn 5000 g/mol), the dry organic solvents and D2O were purchased from Sigma-Aldrich (France). The DHBC PEO-b-PMAA, was purchased from Polymer Source (Canada). The diblock copolymers and homopolymers were used as received unless otherwise specified. Dry chloroform, diethyl ether and deuterated chloroform (CDCI3, Cambridge Isotope) were used as received. 

Fractions of high molecular weight PEO and various pure oligomers were described in the previous section. Deuterated methanol was obtained from Merck Sharpe and Dohme of Canada. Potassium iodide was obtained from Baker and Adamson. Dimethoxyethane was obtained from Matheson Coleman and Bell, purified by distillation, and used as a monomeric analog. 

A set of representative NMR spectra of the ethylene protons of PEO s, 1% in deuterated methanol, with and without the presence of 0.05 M potassium iodide is presented in Figure 1. The introduction of potassium iodide into the PEO solutions has little effect on the NMR spectra of the Ei protons for oligomers ( <6), but the spectrum of the heptamer is significantly changed into two partially resolved peaks. The NMR spectra of the higher members (n>7) of the series are all affected by potassium iodide, although the apparent influence becomes less pronounced for high... 

Fig. 1. Representative NMR spectra of the ethylene protons of 1 % PEO in deuterated methanol (A) Dimethoxy ethane, (B) Tri-ethylene glycol, (C) Tetra-ethylene glycol, (D) Penta-ethylene glycol, (E) Hexa-ethylene glycol, (F) Hepta-ethylene glycol, (G) PEO-400 ( = 9), (H) PEO-600 (w=13), (I) PEO-1000 ( = 22), (J) PEO-6000 ( =140) (A -F) are the corresponding samples of (A-J) with the presence of 0.05 M potassium iodide.

PEO samples, having molecular weights of 4000, 6000 and 300000 were used in this study. These materials, designated PEO-4000, PEO-6000 and PEO-300000 have been described in a previous article [11]. Deuterated methanol - d4, water and chloroform were obtained from Merck Sharpe and Dohme of Canada, and used without any further purification. All the other halogenated solvents were purified according to established procedures. Potassium iodide and potassium sulfate were obtained from Baker and Adamson and were used without further purification. 

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