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31.
Erik Geissler Anne-Marie Hecht Simon Mallam Ferenc Horkay Mikls Zrinyi 《Macromolecular Symposia》1990,40(1):101-108
Small angle neutron scattering measurements were performed on polydimethylsiloxane-toluene solutions and gels at different degrees of swelling. The scattering signal of the gel was decomposed into a solution-like part and a static part. The thermodynamic information obtained from the solution-like part of the signal is compared with macroscopic swelling pressure observations. 相似文献
32.
Delphine Prvot Christophe Galliot Anne-Marie Caminade Jean Pierre Majoral 《Heteroatom Chemistry》1995,6(4):313-318
Phosphorus dialdehydes RP (OC6H4CHO)2 (R = Ph, Me2N) react with phosphodihydrazides PhP(Y)-[N(CH3)NH2]2 (Y = S, O) to give macrocycles 6a–c arising from [2 + 2] cyclocondensation reactions. Treatment of phosphodihydrazone PhP(S) [OC6H4CH N–N(Me)H]2 7 with phenyldichlorophosphine affords macrocycle 8 possessing tri and tetracoordinated phosphorus atoms. Clean desulfurization of thiophosphorus macrocycles 9 and 12 gives rise selectively to new tricoordinated phosphorus containing macrocycles 11 and 13 . 相似文献
33.
For swollen polymer networks there is no generally accepted relation between the macroscopic osmotic properties and the scattering behaviour. Detailed information on the relationship between these properties can, however, be deduced from complementary measurements of osmotic and elastic behaviour, small angle neutron and X-ray scattering (SANS and SAXS) and quasi-elastic light scattering. We describe such an investigation in two types of networks, differing in the mechanism of cross-linking. The SANS spectra yield information on the structure, which is generated both by the dynamics of the system and by long range static constraints. The former, arising from thermodynamic concentration fluctuations, governs the macroscopic osmotic and elastic moduli of the swollen network. The static superstructure in the gel reflects local variations in the cross-link density. The resulting concentration polydispersity, <δφ2>/φ2, is determined by the details of the cross-linking procedure. Its concentration dependence as a function of gel swelling can be expressed in terms of the same macroscopic osmotic and elastic variables as those that govern the thermodynamic properties of the gel. 相似文献
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Clément Barrière Virginie Latour Pierre Fau Anne-Marie Caminade Cédric-Olivier Turrin 《Tetrahedron letters》2012,53(15):1908-1911
We present a simple strategy to obtain non-symmetrical polyethylene glycols equipped with telechelic phosphorus-containing dendrimeric moieties having adhesive phosphonate surface functions. The dendronized PEG tails were characterized by means of multi-nucleus NMR. The grafting abilities of model symmetrical PEG compounds equipped with telechelic amino-bis(methylene-dimethylphosphonates) and amino-bis(methylenephosphonic acids) were rapidly screened on plasma treated silicon wafers and activated silica. 相似文献
37.
Besides properties commonly found for all types of dendrimers, phosphorus-containing dendrimers possess some specific properties seldom or never found for other types of dendrimers. Emphasis will be put on these specificities. 相似文献
38.
We report the high resolution emission (S1 → S0, T1 → S0) and laser single site singlet excitation (S1 ← S0) spectra for the various insertion sites of coronene in n-heptane cooled to 1.5 K. The observation of site splitting of doubly degenerate vibrations and weak electric dipole forbidden 0, 0 bands in the S1 → S0 and T1 → S0 spectra indicates that the ground state, the first excited singlet and lowest triplet states are all distorted. In these spectra, the intensity distribution of the various sites in the 0, 0 bands suggests that the distortion is different from site to site but similar in S0, S1 and T1. Identical ordering of the sites in S1 S0 and S1 S0 spectra as well as the observation of weak shifts in the vibrational frequencies in the two states implies the absence of strong pseudo Jahn-Teller forces in the first excited singlet state. We propose, further, that this is also true for the triplet state. This conclusion is supported by the similarity in zero-field splitting parameters of coronene and deuterated coronene. Taken together, these results indicate strongly that the distortion of coronene in n-heptane is primarily crystal field induced and is not greatly changed upon excitation of the molecule to its lowest excited states. 相似文献
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