Synchrotron X-ray investigations into the lamellar gel phase formed in pharmaceutical creams prepared with cetrimide and fatty alcohols

2000 ◽  
Vol 203 (1-2) ◽  
pp. 127-139 ◽  
Author(s):  
G.M Eccleston ◽  
M.K Behan-Martin ◽  
G.R Jones ◽  
E Towns-Andrews
1980 ◽  
Vol 35 (6) ◽  
pp. 643-644 ◽  
Author(s):  
M. Hentschel ◽  
R. Hosemann ◽  
W. Helfrich

Direction and angle of molecular tilt in an ordered multilayer system of dipalmitoyl lecithin and water were directly determined by X-ray diffraction as a function of temperature in the gel phase with ca. 20 wt. % of water


2013 ◽  
Vol 700 ◽  
pp. 136-139
Author(s):  
Xin Tang ◽  
Jin Huang

The mechanical properties and microstructure of cement stone containing different sodium chloride (NaCl) have been investigated. Uni-axial compression experiments were used to study mechanical properties. The main crystalline phase composition of cement specimens was determined by means of X-ray diffraction (XRD). Surface morphology of cement stone was observed by using scanning electron microscopy (SEM). The obtained results showed that compared with the other samples, the sample incorporated 14% sodium chloride was quite different, whose compressive strength was higher and microstructure was denser. The sodium chloride crystalline phase and the hydration (C-S-H) gel phase co-existed.


2009 ◽  
Vol 96 (3) ◽  
pp. 133a
Author(s):  
Joanna Deek ◽  
Jayna Jones ◽  
Roy Beck ◽  
Cyrus R. Safinya

2015 ◽  
Vol 68 (5) ◽  
pp. 836
Author(s):  
Min Xue ◽  
Chunmeng Yu ◽  
Gang Wang ◽  
Hang Yu ◽  
Yu Fang

Two novel tri-cholesteryl derivatives 1 and 2 have been designed and prepared. Gelation tests in 30 liquids revealed that 1 is a more efficient gelator than 2. Interestingly, the gel of 1/cyclohexane shows a reversible sol–gel phase transition in response to a variety of disparate stimuli such as temperature, stress, and HCl gas. In particular, a fully reversible thixotropic property was observed, which has been rarely reported before. Fourier transform infrared spectroscopy and 1H NMR measurements revealed that hydrogen bonding is an important driving force for the formation of the gel networks. The network structures of 1 and 2 in their cyclohexane gels were studied by scanning electron microscopy and X-ray diffraction analyses, and possible packing models were proposed accordingly. The findings demonstrated in the present work suggest that there is a big potential for developing tri-cholesteryl derivatives into extraordinary low molecular mass gelators.


2019 ◽  
Vol 218 ◽  
pp. 168-177 ◽  
Author(s):  
John F. Nagle ◽  
Pierre Cognet ◽  
Fernando G. Dupuy ◽  
Stephanie Tristram-Nagle
Keyword(s):  
X Ray ◽  

Langmuir ◽  
1995 ◽  
Vol 11 (10) ◽  
pp. 3676-3684 ◽  
Author(s):  
Hans von Berlepsch ◽  
Dieter Hofmann ◽  
Johannes Ganster

2002 ◽  
Vol 83 (6) ◽  
pp. 3324-3335 ◽  
Author(s):  
Stephanie Tristram-Nagle ◽  
Yufeng Liu ◽  
Justin Legleiter ◽  
John F. Nagle
Keyword(s):  
X Ray ◽  

2019 ◽  
Vol 52 (5) ◽  
pp. 1169-1175 ◽  
Author(s):  
Jitendra Bahadur ◽  
Avik Das ◽  
Debasis Sen

Time-resolved small-angle X-ray scattering (SAXS) measurements have been carried out using the newly developed SAXS beamline at the Indus-2 synchrotron source to study the evaporation-induced structural evolution of the lamellar mesophase. An aqueous dispersion of sodium dodecyl sulfate (SDS) of ∼0.60 volume fraction at room temperature results in a gel phase due to random jamming of the lamellar structured entities. Thermal analysis of SDS in the powder phase shows three distinct phenomena corresponding to evaporation of free and bound water, followed by thermal dissociation of SDS molecules. Time-resolved in situ SAXS measurements during evaporation of the gel under ambient conditions reveal two regimes of structural evolution of the lamellar phase. The evaporation rate in the first phase of evaporation up to 60 min is roughly six times faster than that in the second phase. A plausible mechanism is proposed to explain this behaviour. The intrusion of water molecules into layers sandwiched between polar head groups forms an additional 7 Å thick layer of water molecules, leading to an increase in the distance between the head groups. The evaporation of the water molecules in the first phase up to 60 min causes a reduction in the lamellar thickness of ∼3 Å. Subsequent evaporation of water molecules in the second phase is quite slow owing to the higher binding energy of these water molecules and the low permeability caused by the reduced lamellar thickness after the first phase of evaporation. The swelling behaviour of the lamellar structure under ambient conditions is found to be reversible and the powder-phase structure is observed after a few days of evaporation of the gel phase.


2019 ◽  
Vol 116 (3) ◽  
pp. 225a
Author(s):  
John F. Nagle ◽  
Pierre Cognet ◽  
Fernando G. Dupuy ◽  
Stephanie A. Tristram-Nagle
Keyword(s):  
X Ray ◽  

1981 ◽  
Vol 256 (14) ◽  
pp. 7528-7535 ◽  
Author(s):  
R. Welti ◽  
D.A. Rintoul ◽  
F. Goodsaid-Zalduondo ◽  
S. Felder ◽  
D.F. Silbert

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