Polylactic acid is proving to be a viable alternative to petrochemical-based plastics for many applications It is produced from renewable resources and is biodegradable, decomposing to give H2O, CO2, and humus, the black material in soil In addition, it has unique physical properties that make it useful in diverse applications including paper coating, fibers, films, and packaging (see Figure)

Polylactic Acid Technology

Nanoparticle interaction with plasma proteins as it relates to particle biodistribution, biocompatibility and therapeutic efficacy.

Morphology evolution via self-organization and lateral and vertical diffusion in polymer:fullerene solar cell blends

Morphology evolution via self-organization and lateral and vertical diffusion in polymer:fullerene solar cell blends.

https://www.zora.uzh.ch/id/eprint/44154/1/Rabe1.pdf

Understanding protein adsorption phenomena at solid surfaces

Protein Nanoparticle Interactions: Opportunities and Challenges Morteza Mahmoudi,* Iseult Lynch, Mohammad Reza Ejtehadi, Marco P. Monopoli, Francesca Baldelli Bombelli, and Sophie Laurent National Cell Bank, Pasteur Institute of Iran, Tehran, Iran Nanotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran School of Chemistry and Chemical Biology & Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland Department of Physics, Sharif University of Technology, Tehran, Iran School of Pharmacy, UEA, Norwich Research Park, Norwich,U.K. Department of General, Organic, and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons, Avenue Maistriau 19, B-7000 Mons, Belgium

Protein-nanoparticle interactions: opportunities and challenges.

We have investigated the effect of sample preparation on the glass-transition temperature (Tg) of thin films of polystyrene (PS). By preparing and measuring the glass-transition temperature Tg of multilayered polymer films, we are able to assess the contribution of the spincoating process to the reduced Tg values often reported for thin PS films. We find that it is possible to determine a Tg even on the first heating cycle, and that by the third heating cycle (a total annealing time of 15 min at T = 393 K) the Tg value has reached a steady state. By comparing multilayered versus single layered films we find that the whole Tg depends only on the total film thickness, and not on the thickness of the individual layers. These results strongly suggest that the spincasting process does not contribute significantly to Tg reductions in thin polymer films. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4503–4507, 2004

Effect of sample preparation on the glass‐transition of thin polystyrene films

A new process has been developed to determine the biological activity of an intact layer of lysozyme deposited onto a biomaterial surface. This process is applied to a number of common hydrogel contact lenses. The activity of the surface-adsorbed protein is measured using a standard micrococcal activity assay, with extra steps to distinguish between protein on the surface and protein in solution. This is in contrast to protein extraction work in which the activity of all adsorbed protein is measured. For ionic materials, which are known to deposit large amounts of protein, particularly positively charged proteins such as lysozyme, there is evidence for loosely bound protein re-entering the solution, thus making it impossible to truly separate out the surface-adsorbed protein. This optimized process provides the first quantification of the biological activity of an intact layer of surface-adsorbed protein at a hydrogel interface. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 755–764, 2013.

Measuring the kinetics and activity of adsorbed proteins: In vitro lysozyme deposited onto hydrogel contact lenses over short time periods†

The film thickness dependence of both the glass transition temperature (T
 g
 ) and the 1 kHz alpha relaxation were studied for thin films of isotactic Poly (methylmethacrylate) (i-PMMA) supported on aluminium substrates. Films in the thickness range 7-200 nm were studied. The ellipsometrically determined T
 g
 was found to show reductions for films thinner than 60 nm, with the largest observed reduction being 12 K for a 7 nm thick film. Measurements of the T
 g
 were also performed on i-PMMA films supported on silicon substrates. Dielectric studies of the temperature dependent 1 kHz alpha relaxation peak, showed that the position (T
 α
 ) and shape of the peak have no film thickness dependence. This was shown to hold for films with one free surface and films with a 30 nm thermally evaporated capping layer. Capping the films was shown to have no effect on the thickness dependence of either T
 g
 or T
 α
 . The implications of these results are discussed further and the different film thickness dependencies of T
 g
 and T
 α
 are discussed. This is done within the framework of the Vogel-Fulcher-Tamann (VFT) theory of glass forming materials and also in the context of the existence of a dynamic correlation length ξ.

Thickness dependence of the dynamics in thin films of isotactic poly (methylmethacrylate)

We have made a detailed characterization of the molecular weight dependence of isothermal gold nanoparticle embedding into the surface of atactic polystyrene films. Polymers in the range 3 × 103 < Mw < 1.2 × 106 g mol−1 were used within a temperature range that encompassed the bulk glass transition temperature, around which both Mw dependence and heterogeneous dynamics were measured. The range in Mw also allows for comparison to recent studies on molecular glass surfaces – essentially covering the entire range of possible polymer sizes. The results show that there is a different manifestation of enhanced surface mobility for large and small polymer molecules. The transition between the mechanisms provides some bound on the size of a surface region with enhanced surface dynamics on glassy polystyrene surfaces.

Molecular weight dependence of near surface dynamical mechanical properties of polymers

/pdf/controlling-marangoni-induced-instabilities-in-spin-cast-51zy14r4ec.pdf

James A. Forrest

Papers

Effect of sample preparation on the glass‐transition of thin polystyrene films

Measuring the kinetics and activity of adsorbed proteins: In vitro lysozyme deposited onto hydrogel contact lenses over short time periods†

Thickness dependence of the dynamics in thin films of isotactic poly (methylmethacrylate)

Molecular weight dependence of near surface dynamical mechanical properties of polymers

Controlling Marangoni induced instabilities in spin-cast polymer films: How to prepare uniform films