高分子材料中性能表征检测方案

Biolin Scientific[ Progress Together] [Application Overview] 2 Polymer studies by QCM-D Polymers are versatile building blocks within applications ranging from plastics usedin everyday life to sophisticated biopolymers for medical devices. Quartz CrystalMicrobalance with Dissipation monitoring， QCM-D， has been used for the characteri-zation of a wide variety of polymers. Introduction Control of polymer build-up， conformation and degradation arekey features in the study and development of polymer basedmaterials. QCM-D provides this control through measuringchanges in both mass and softness (related to energy dissipation)of polymer layers in real-time. [Figure 1]： Illustration of polymers adsorbing in a brush (top) or pancake(bottom) conformation. [Figure 2]： Thickness of multilayer after each polyelectrolyte deposition，measured with QCM-D. Grafted polymer conformation and phase transition[1] Build-up and control of polyelectrolyte multilayers [2] Polymers grafted to a surface can adopt several differentconformations. The ability to control these transitions increasesthe applicability of the material. In this study QCM-D waschosen specifically for the sensitivity of the technique to studychanges in polymer conformation. It was possible to control theconformation of the polymers in situ and in real-time by alteringtemperature and grafting density and also to identify differentphases in the polymer adsorption process. Polyelectrolyte multilayers are used to modify surfaces in a vastnumber of applications thanks to their flexibility and robustness.Even though they are simple to build， the mechanisms of howdifferent conditions affect the build-up is not well understood.QCM-D is an ideal tool to get better understanding of this as itcan study the build-up of hydrated films in real-time. In this studypolyelectrolyte multilayers were evaluated in terms of thicknessper layer and the influence of salt concentration on build-up rateand total thickness. [Figure 3]： Illustration showing the frequency and dissipation shifts ashyaluronan (blue in illustration) is immobilized and later cross-linked by tumornecrosis factor-stimulated gene-6 (TSG-6) (green ovals). Biopolymer grafting and cross-linking through specificinteraction [3] Hyaluronan is one of the most abundant polymers in theextracellular matrix and it is of great interest to see how itinteracts with biomolecules. In this study the focus was on theinflammation related protein TSG-6 and how this cross-linkshyaluronan. The dramatic decrease in the QCM-D signal showingenergy dissipation (Fig. 3) at TSG-6 exposure made the authorsdetermine that hyaluronan collapses into a stiffer film wheninteracting with TSG-6. This provides valuable understanding ofhow the structure of the extracellular matrix is remodeled duringinflammatory processes. ( References： ) ( [1] Zhang， G.， Wu， C .， Quartz crystal microbalance s tudies on c onformationalchange of polymer chains at interface. Macromolecular Rapid Communica-tions， 30 (4-5)， 328-335， 2009 ) ( [2] Zan， X.， Pe ng ， B.， Hoagland， D .A.， Su， Z.， Polyelectrolyte uptake by PE Ms： Im pact o f sa l t concentration. Po ly m.Chem.， 2，2581-2589，2 0 1 1 ) ( [3] Baranova， N. S.， Nileback ， E . ， H aller， F. M.， Briggs， D. C. ， Svedhem， S .， Day， A. J .， Richter， R. P . ， The inflammation-associated p r ot ein T S G -6 cross-links ) ( hyaluronan via hyaluronan-induced TSG-6 oligomers.J. Biol. C h em.， 2 8 6 (29)， 25675-25686，2011 ) 4 [ Progress Together] E-mail：info@biolinscientific.combiolinscientific.com []Q-Sense A Biolin Scientific[]Q-Sense AO