溶液中疏水改性多聚糖在气水界面的聚集检测方案(椭偏仪)

SpectroscopicEllipsometry Ellipsometric Study of the Aggregation ofHydrophobically Modified Polysaccharidesin Solution at the Air / Water Interface UVISEL Michel Stchakovsky -Application Scientist - Thin Film Division Pullulan is a natural， water-soluble polysaccharide used in the production of foods， pharmaceuticals andcosmetics. From the consumer side it is popular as it is of non-animal origin being manufactured fromcorn， and from the technical side it is easily formed into films suitable for use in capsules. In this study， we have compared the physico-chemical properties of two ionic pullulan derivatives (CMP)modified by 10% and 35% Cg chains in aqueous solutions. These derivatives exhibit an associative behav-iour which stems from intra and intermolecular interactions between the hydrophobic C； groups graftedonto the molecules. Characterisation of the CMP polymer solutions The work was performed using a Jobin Yvon UVISEL Visible Spectroscopic Phase Modulated Ellipsome-ter. To make meaningful measurements of ellipsometric spectra requires the ultimate sensitivity for the tech-nique as the contrast in refractive index between the solvent and polymer molecules is extremely weak.The measurements described here were made at an incident angle close to 53° (which is the Brewsterangle for the system under consideration)， across the spectral range 250-800 nm. Moreover， such transparent ultrathin layered systems generate a A angle near 0 [180]. When com-pared to conventional ellipsometers， the phase modulated ellipsometer configuration is unique inthat it allows the highest sensitivity and precision of the A angle across the full [0°， 360°] range， evenwhen A is close to 0°. Explore the future HORIBAGROUP SpectroscopicElipsometry The figure shows three spectra of the ellipsometric angles W and ▲showing how the signals changewithin 10 minutes after perturbation of the air/liquid interface. The effect can be observed on themolecules modified by 10% C； chains only. Change in surface properties measured 3 timesduring a 10 minute interval for 10% modified. Stable surface for 35% modified measured3 times. -360.000 -340.000 -320.000 -300.000 -280.000 A() -260.000 -240.000 -220.000 -200.000 -180.000 Conclusion This interpretation has been supported by both surface tension measurement for the liquid phase and fluorescence spec-troscopy for bulk behaviour. From this study there is clear evidence that increasing the substitution rate from 10% to 35% induces a reinforcement ofthe hydrophobic interactions and thus the formation of more compact and stable aggregates which can complex hydro-phobic compounds. The use of CMP 35% C； could be envisaged in drug formulations where dispersion of a hydrophobicdrug in an aqueous phase is required. The authors would like to thank Veronique Rosilio from Paris-Sud University for her support in this work. France： USA： Jobin Yvon S.A.S.Jobin Yvon Inc.Z.A. De la Vigne aux Loups3880 Park AvenueJY Germany：+49 (0)894623 17-05， Avenue AragoEdison， NJ 08820-3012JY Italy： +39 0 2 5760 305091380Chilly MazarinToll-Free：1-866-jobinyvonJY Japan： +81 (0)33861 8231Tel： +33 (0) 1 64 54 13 00Tel：+1-732-494-8660JY UK：+44 (0) 20 8204 8142Fax： +33(0) 1 69 74 88 61Fax：+1-732-549-5125JY China： +86 (0) 10 6849 2216Email： tfd-sales@jobinyvon.frEmail： info@jobinyvon.comJY Korea：+82 2 576 8650 EMISSION·FLUORESCENCE·FORENSICS· GRATINGSG OEM·OPTICAL SPECTROSCOPY·RAMAN·THIN FILM This interpretation has been supported by both surface tension measurement for the liquid phase and fluorescence spectroscopy for bulk behaviour.From this study there is clear evidence that increasing the substitution rate from 10% to 35% induces a reinforcement of the hydrophobic interactions and thus the formation of more compact and stable aggregates which can complex hydrophobic compounds. The use of CMP 35% C8 could be envisaged in drug formulations where dispersion of a hydrophobic drug in an aqueous phase is required.