Excimer fluorescence as a molecular probe of blend miscibility. 4. Effect of temperature in solvent casting

1981 ◽  
Vol 14 (5) ◽  
pp. 1558-1567 ◽  
Author(s):  
Muhammad Amin Gashgari ◽  
Curtis W. Frank
Keyword(s):  
Molecular Probe ◽  
Effect Of Temperature ◽  
Solvent Casting ◽  
Excimer Fluorescence

Pyrene Fluorescence as a Molecular Probe of Miscibility in Organic/Inorganic Hybrid Nanocomposites Suitable for Microelectronic Applications

2002 ◽  
Vol 726 ◽  
Author(s):  
Q. R. Huang ◽  
David Mecerreyes ◽  
James L. Hedrick ◽  
Willi Volksen ◽  
Curtis W. Frank ◽  
...  
Keyword(s):  
Hybrid Nanocomposites ◽  
Molecular Probe ◽  
Excimer Fluorescence ◽  
Neat Polymer ◽  
Loading Level ◽  
Pyrene Fluorescence ◽  
Low Dielectric ◽  
Low Dielectric Constant Materials ◽  
Phase Separation Behavior ◽  
Separation Behavior

AbstractFluorescence spectroscopy has been used to study the miscibility of methyl silsesquioxane (MSSQ)/poly(methyl methacrylate-co-dimethylaminoethyl methacrylate) [P(MMA-co-DMAEMA)] hybrid nanocomposites, which are useful in fabricating the next generation of spin-on, ultra-low dielectric constant materials in the microelectronic industries. In this work, we have attached the pyrene group into the PMMA side chains. MSSQ with different amount of initial -SiOH (silanol) endgroups are used to study the effect of endgroup functionality on the phase separation behavior of the hybrid nanocomposites. Pyrene excimer fluorescence results reveal that MSSQ is miscible with P(MMA-co-DMAEMA) only up to 6 wt% P(MMA-co-DMAEMA) loading level, thus establishing an upper limit on local miscibility with MSSQ. As the P(MMA-co-DMAEMA) loading level increases, the excimer to monomer ratios also increase, suggesting that the MSSQ/P(MMA-co-DMAEMA) hybrid nanocomposites move toward greater immiscibility. This ratio approaches that of the neat polymer for domain sizes > 5 nm (SAXS, SANS). The fluorescence results also show that, the lower the amount of initial silanol groups in MSSQ, the greater the immiscibility of the MSSQ and porogen, which ultimately translates into larger pores upon porogen burnout.

Role of Temperature Change on Poly(DL-lactic acid) Porous Matrix Film Fabrication by Solvent Casting Method

2014 ◽  
Vol 1060 ◽  
pp. 184-187 ◽  
Author(s):  
Sasiprapa Chitrattha ◽  
Thawatchai Phaechamud
Keyword(s):  
Lactic Acid ◽  
Porous Structure ◽  
Temperature Change ◽  
Room Temperature ◽  
Porous Matrix ◽  
Effect Of Temperature ◽  
Poly Lactic Acid ◽  
Solvent Casting ◽  
Porous Films ◽  
Casting Method

Poly(lactic acid) (PLA) has a variety of applications. It has been widely used in the biomedical and pharmaceutical fields due to its biocompatibility and biodegradability. Polyethylene glycol (PEG) is used as an inactive ingredient in the pharmaceutical industry as a solvent, plasticizer, surfactant, ointment base, suppository base, tablet lubricant and capsule lubricant. The aim of this study was to determine the effect of temperature change on PLA porous matrix film fabricating by solvent casting method with an addition of PEG400 to improve and increase the pore interconnectivity. Their mechanical properties such as tensile strength (TS) and % elongation at break (%E) and morphology were investigated. Porous films were prepared at 4 °C for 24 h and dry at room temperature for 24 h (4CRT), 4 °C for 24 h and dry at 60 °C for 24 h (4C60C), -20 °C for 24 h and dry at room temperature for 24 h (-20CRT), -20 °C for 24 h and dry at 60 °C for 24 h (-20C60C), -80 °C for 24 h and dry at room temperature for 24 h (-80CRT), and -80 °C for 24 h and dry at 60 °C for 24 h (-80C60C). 4C60C exhibited the highest strength and toughest, however all of samples showed the quite soft behavior. From topography study they displayed the different porous structure which sample of 4C60C displayed the smallest porous structure. Therefore, the temperature change between the fabrication processes affected the TS, %E and morphology structure of PLA porous matrix films.

Sign in / Sign up

Export Citation Format

Share Document