scholarly journals Influence of Solvent and Substrate on Hydrophobicity of PLA Films

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4289
Author(s):  
Verónica Luque-Agudo ◽  
Amparo M. Gallardo-Moreno ◽  
María Luisa González-Martín
Keyword(s):  
Surface Tension ◽  
Polylactic Acid ◽  
Surface Properties ◽  
Bacterial Adhesion ◽  
Spatial Arrangement ◽  
Methyl Groups ◽  
Solvent Casting ◽  
Properties Of Materials ◽  
The Right ◽  
Influence Of Solvent

The study of the surface properties of materials is key in determining whether the material will be suitable for medical purposes. One of these properties is hydrophobicity, which is important when assessing its behavior against bacterial adhesion. In this work, we have studied the influence of the solvent (chloroform, acetone, and tetrahydrofuran) and the substrate (glass, PTFE, silicone, and Ti6Al4V) on which polylactic acid is deposited in solution to manufacture films by solvent-casting. Thus, it has been found that there are no significant differences in hydrophobicity and surface tension among the solvents evaluated, but there are significant differences with respect to the substrates: PLA films casted on silicone are hydrophobic, while those casted on the rest of the substrates are hydrophilic. This is related to the fact that the silicone interacts with the polymer modifying its spatial arrangement, exposing its methyl groups towards the interface with the air. In this way, it has been shown that, when manufacturing PLA films, it is important to choose the right surface on which to deposit them, depending on their desired function.

scholarly journals Antimicrobial Active Bioplastics Using Triangular Silver Nanoplate Integrated Polycaprolactone and Polylactic Acid Films

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1132
Author(s):  
Eduardo Lanzagorta Garcia ◽  
Olivia A. Attallah ◽  
Marija Mojicevic ◽  
Declan M Devine ◽  
Margaret Brennan Fournet
Keyword(s):  
Polylactic Acid ◽  
Scale Up ◽  
Composite Films ◽  
Antimicrobial Properties ◽  
Morphological Structure ◽  
Antimicrobial Effect ◽  
Solvent Casting ◽  
Local Surface Plasmon Resonance ◽  
Casting Technique ◽  
Triangular Silver Nanoplates

An innovative antimicrobial technology for plastic surfaces is presented. We report the synthesis and scale-up of triangular silver nanoplates (TSNPs) and their integration into polycaprolactone (PCL) and polylactic acid (PLA) polymers through a solvent-casting technique. The TSNPs have a high geometric aspect ratio and strong local surface plasmon resonance (LSPR) response, which provides an effective tool for monitoring their integrity during processing and integration with the biodegradable plastics. An aqueous-based seed-mediated chemical method was used to synthesize the TSNPs, and characterisation was carried out using TEM and UV (Ultraviolet)-VIS (Visible) spectroscopy to measure LSPR profiles. The UV-VIS spectra of silver seeds and TSNPs exhibited characteristic peaks at 395 and 600 nm respectively. Synthesized TSNPs were coated with thiol-terminated polyethylene glycol (SH-PEG) and transferred into chloroform in order to effect compatibility with PCL and PLA. TSNP/PCL and TSNP/PLA composite films were prepared by solvent casting. The morphological structure, thermal, mechanical, and antimicrobial properties of the TSNP-incorporated composite films were evaluated. Results showed the TSNP-treated films had a rougher surface than the bare films. Insignificant changes in the thermal properties of TSNP-treated films compared to bare ones were also observed, which indicated the thermal stability of the composite films. The tensile strength and antimicrobial properties of the composite films were increased after TSNP incorporation. TSNP/PCL and TSNP/PLA films exhibited improved antimicrobial activity against Escherichia coli and Staphylococcus aureus with antimicrobial effect (AE) values ranging between 0.10 and 0.35. The obtained results and demonstrated TSNP production scalability validate the TSNP treated PCL and PLA films as a composite material with desirable antimicrobial effect for wide-ranging surface applications.

scholarly journals Study on the influence of advanced treatment processes on the surface properties of polylactic acid for a bio-based circular economy for plastics

2021 ◽  
pp. 105627
Author(s):  
Georgia Sourkouni ◽  
Charalampia Kalogirou ◽  
Philipp Moritz ◽  
Anna Gödde ◽  
Pavlos K. Pandis ◽  
...  
Keyword(s):  
Polylactic Acid ◽  
Surface Properties ◽  
Circular Economy ◽  
Advanced Treatment ◽  
Treatment Processes

Increasing Storage Modulus, Contact Angle and Surface Tension of Airway Mucus Increases Clearance by Simulated Cough Through a Model Trachea

2010 ◽  
Author(s):  
Anpalaki J. Ragavan ◽  
Cahit A. Evrensel ◽  
Peter Krumpe
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Storage Modulus ◽  
Surface Properties ◽  
Respiratory Diseases ◽  
Interactive Effects ◽  
Altered Surface ◽  
Human Trachea ◽  
Tension Increase ◽  
And Storage

Altered surface and viscoelastic material properties of mucus during respiratory diseases have a strong influence on its clearance by cilia and cough. Combined effects of the surface properties (contact angle and surface tension) and storage modulus with relatively unchanged viscosity on displacement of the simulated mucus aliquot during simulated cough through a model adult human trachea is investigated. For the mucus simulants used in this study contact angle and surface tension increase significantly as storage modulus increase while viscosity remains practically unchanged. Displacement of mucus simulant aliquots increased significantly with increasing storage modulus (and contact angle) at a given cough velocity in the range between 5 meters/second (m/s) and 30 m/s with duration 0.3 s. Results suggest that the interactive effects of elasticity and surface properties may help facilitate mucus displacement at low cough velocities.

Effect of low-temperature plasma treatment and γ-irradiation on the surface properties of thin films based on polylactic acid

2020 ◽  
Vol 6 ◽  
pp. 40-55
Author(s):  
N.M. Ivanova ◽  
◽  
E.O. Filippova ◽  
A.N. Aleinik ◽  
V.F. Pichugin ◽  
...  
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Low Temperature ◽  
Polylactic Acid ◽  
Surface Properties ◽  
Polar Component ◽  
Low Temperature Plasma ◽  
Plasma Exposure ◽  
Γ Irradiation ◽  
Temperature Plasma

Effects of the low-temperature plasma exposure, γ-irradiation, and joint g-irradiation and plasma exposure on the structure and surface properties of thin films based on polylactic acid (PLA) have been investigated. Films were obtained by the method a solvent-casting. It has been shown that films based on polylactic acid have topographically different sides: a smoother inner side and embossed outer one. PLA films have properties close to those hydrophobic, with a contact angle in the range of 70°-73° regardless of the surface side and belong to a weakly polar materials. The combined effect of plasma and gamma radiation slightly changes the surface topography. The effect of low-temperature plasma on the surface of the films leads to a decrease in the contact angle by 13°-55° (9-11%) and an increase in surface energy due to the polar component. The results of in vivo experiments on rabbits are presented. Biomicroscopy, optical coherence tomography, morphological and electron microscopic examination of the cornea after implantation of initial and radiation and plasma treated films showed that implantation of the films in the anterior chamber is not accompanied by a pronounced inflammatory reaction and increased intraocular pressure, while maintaining the morphological structure of the cornea almost unchanged.

Comparison of Four Surfactants: In Vitro Surface Properties and Responses of Preterm Lambs to Treatment at Birth

PEDIATRICS ◽  
1987 ◽  
Vol 79 (1) ◽  
pp. 38-46
Author(s):  
Machiko Ikegami ◽  
Yotaro Agata ◽  
Tarek Elkady ◽  
Mikko Hallman ◽  
David Berry ◽  
...  
Keyword(s):  
Surface Tension ◽  
Surface Properties ◽  
Surface Adsorption ◽  
Soluble Proteins ◽  
The Other ◽  
Clinical Responses ◽  
Spreading Rates ◽  
Surface Spreading

Natural sheep surfactant, rabbit surfactant, human surfactant, and surfactant TA were compared for in vitro surface properties and for responses of preterm lambs to treatment. Equivalent amounts of sheep, rabbit, and human surfactants were needed to lower the surface tension to less than 10 dynes/cm, whereas four times less surfactant TA similarly lowered the surface tension. Surface-spreading rates were similar for the surfactants. The surface adsorption of the batch of human surfactant tested was much slower than was adsorption of the other surfactants. Ventilation was significantly improved in all surfactant-treated lambs relative to the control lambs, indicating the general efficacy of the surfactant treatments. Overall, surfactant TA had the best in vitro characteristics, yet the preterm lambs treated at birth with surfactant TA had lower Po2 values and higher ventilatory requirements than did the sheep surfactant-treated lambs. The in vivo responses to rabbit surfactant were intermediate between the responses to sheep surfactant and to surfactant TA. Human surfactant resulted in the least effective clinical response. More of the phosphatidylcholine associated with human surfactant and surfactant TA was lost from the alveoli and lung tissue after four hours of ventilation than was lost from sheep or rabbit surfactant-treated lambs. More intravascular radiolabeled albumin leaked into the alveoli of the surfactant TA-treated lambs than sheep or rabbit surfactant-treated. lambs. The four surfactants also had different sensitivities to the effects on minimum surface tensions of the soluble proteins present in alveolar washes. The study demonstrates that the range of clinical responses was not predictable based on the in vitro surface properties that we measured. The surfactants behaved differently with respect to loss from the lungs and sensitivity to soluble proteins. Factors other than surface properties are important for the in vivo responses to surfactant treatments.

scholarly journals Structures, Optical and Mechanical Properties of PLA/ZnO SiO2 Al2O3 Composite Elaborated by a Solvent Casting Method

Proceedings ◽  
2019 ◽  
Vol 26 (1) ◽  
pp. 18
Author(s):  
Bouamer ◽  
Benrekaa ◽  
Younes
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Solvent Casting ◽  
Casting Method ◽  
Al2o3 Composite ◽  
Optical And Mechanical Properties

In this study, granulated polylactic acid and ZnO, SiO2 and Al2O3 powders were mixed to form PLA/ZnO and PLA/ZnO SiO2 Al2O3 composites with different concentrations using a solvent casting method. [...]

Surface tension and pulmonary compliance in premature rabbits

1989 ◽  
Vol 66 (5) ◽  
pp. 2039-2044 ◽  
Author(s):  
M. R. Mercurio ◽  
J. M. Fiascone ◽  
D. M. Lima ◽  
H. C. Jacobs
Keyword(s):  
Surface Tension ◽  
Surface Properties ◽  
Pulmonary Surfactant ◽  
Dynamic Compliance ◽  
Ringer Solution ◽  
Tween 20 ◽  
Adult Rabbit ◽  
Equilibrium Surface ◽  
Equilibrium Surface Tension ◽  
Pulmonary Compliance

In vitro surface properties of pulmonary surfactant thought to be essential to its ability to increase pulmonary compliance include minimum surface tension less than 10 dyn/cm and large surface tension variability and hysteresis. We tested four surface-active agents (Tween 20, a detergent; and FC-100, FC-430, and FC-431, industrial fluorocarbons), all lacking these properties, for their ability to increase pulmonary compliance in surfactant-deficient premature rabbits. Fetal rabbits were delivered by cesarean section at 27 days (full term = 31 days) and injected via tracheostomy with 50% lactated Ringer solution, adult rabbit surfactant, or one of the four experimental agents. Dynamic compliance was measured using 1 h of mechanical ventilation followed by alveolar lavage. Each experimental agent produced a dynamic compliance significantly higher than 50% lactated Ringer solution and statistically equal to or greater than natural surfactant. Equilibrium surface tension of the agents and minimum and equilibrium surface tension of the alveolar washes each correlated with compliance (P less than 0.05). This suggests that some surface properties of pulmonary surfactant believed to be essential are not, although surface tension does seem to play a role in pulmonary compliance.

Alterations in the surface properties of lung surfactant in the torpid marsupial Sminthopsis crassicaudata

1998 ◽  
Vol 84 (1) ◽  
pp. 146-156 ◽  
Author(s):  
Olga V. Lopatko ◽  
Sandra Orgeig ◽  
Christopher B. Daniels ◽  
David Palmer
Keyword(s):  
Surface Tension ◽  
Surface Properties ◽  
Surface Activity ◽  
Pulmonary Surfactant ◽  
Lung Surfactant ◽  
Lung Compliance ◽  
Equilibrium Surface Tension ◽  
Sminthopsis Crassicaudata

Lopatko, Olga V., Sandra Orgeig, Christopher B. Daniels, and David Palmer. Alterations in the surface properties of lung surfactant in the torpid marsupial Sminthopsis crassicaudata. J. Appl. Physiol. 84(1): 146–156, 1998.—Torpor changes the composition of pulmonary surfactant (PS) in the dunnart Sminthopsis crassicaudata [C. Langman, S. Orgeig, and C. B. Daniels. Am. J. Physiol. 271 ( Regulatory Integrative Comp. Physiol. 40): R437–R445, 1996]. Here we investigated the surface activity of PS in vitro. Five micrograms of phospholipid per centimeter squared surface area of whole lavage (from mice or from warm-active, 4-, or 8-h torpid dunnarts) were applied dropwise onto the subphase of a Wilhelmy-Langmuir balance at 20°C and stabilized for 20 min. After 4 h of torpor, the adsorption rate increased, and equilibrium surface tension (STeq), minimal surface tension (STmin), and the %area compression required to achieve STmin decreased, compared with the warm-active group. After 8 h of torpor, STmin decreased [from 5.2 ± 0.3 to 4.1 ± 0.3 (SE) mN/m]; %area compression required to achieve STmindecreased (from 43.4 ± 1.0 to 27.4 ± 0.8); the rate of adsorption decreased; and STeqincreased (from 26.3 ± 0.5 to 38.6 ± 1.3 mN/m). ST-area isotherms of warm-active dunnarts and mice at 20°C had a shoulder on compression and a plateau on expansion. These disappeared on the isotherms of torpid dunnarts. Samples of whole lavage (from warm-active and 8-h torpor groups) containing 100 μg phospholipid/ml were studied by using a captive-bubble surfactometer at 37°C. After 8 h of torpor, STmin increased (from 6.4 ± 0.3 to 9.1 ± 0.3 mN/m) and %area compression decreased in the 2nd (from 88.6 ± 1.7 to 82.1 ± 2.0) and 3rd (from 89.1 ± 0.8 to 84.9 ± 1.8) compression-expansion cycles, compared with warm-active dunnarts. ST-area isotherms of warm-active dunnarts at 37°C did not have a shoulder on compression. This shoulder appeared on the isotherms of torpid dunnarts. In conclusion, there is a strong correlation between in vitro changes in surface activity and in vivo changes in lipid composition of PS during torpor, although static lung compliance remained unchanged (see Langman et al. cited above). Surfactant from torpid animals is more active at 20°C and less active at 37°C than that of warm-active animals, which may represent a respiratory adaptation to low body temperatures of torpid dunnarts.

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