scholarly journals Fabrication of hybrid nanocomposite scaffolds by incorporating ligand-free hydroxyapatite nanoparticles into biodegradable polymer scaffolds and release studies

2015 ◽  
Vol 6 ◽  
pp. 2217-2223 ◽  
Author(s):  
Balazs Farkas ◽  
Marina Rodio ◽  
Ilaria Romano ◽  
Alberto Diaspro ◽  
Romuald Intartaglia ◽  
...  

We report on the optical fabrication approach of preparing free-standing composite thin films of hydroxyapatite (HA) and biodegradable polymers by combining pulsed laser ablation in liquid and mask-projection excimer laser stereolithography (MPExSL). Ligand-free HA nanoparticles were prepared by ultrafast laser ablation of a HA target in a solvent, and then the nanoparticles were dispersed into the liquid polymer resin prior to the photocuring process using MPExSL. The resin is poly(propylene fumarate) (PPF), a photo-polymerizable, biodegradable material. The polymer is blended with diethyl fumarate in 7:3 w/w to adjust the resin viscosity. The evaluation of the structural and mechanical properties of the fabricated hybrid thin film was performed by means of SEM and nanoindentation, respectively, while the chemical and degradation studies were conducted through thermogravimetric analysis, and FTIR. The photocuring efficiency was found to be dependent on the nanoparticle concentration. The MPExSL process yielded PPF thin films with a stable and homogenous dispersion of the embedded HA nanoparticles. Here, it was not possible to tune the stiffness and hardness of the scaffolds by varying the laser parameters, although this was observed for regular PPF scaffolds. Finally, the gradual release of the hydroxyapatite nanoparticles over thin film biodegradation is reported.

Author(s):  
M. Grant Norton ◽  
C. Barry Carter

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.


1991 ◽  
Vol 239 ◽  
Author(s):  
J. Ruud ◽  
D. Josell ◽  
A. L. Greer ◽  
F. Spaepen

ABSTRACTA new design for a thin film microtensile tester is presented. The strain is measured directly on the free-standing thin film from the displacement of laser spots diffracted from a thin grating applied to its surface by photolithography. The diffraction grating is two-dimensional, allowing strain measurement both along and transverse to the tensile direction. In principle, both Young's modulus and Poisson's ratio of a thin film can be determined. Ag thin films with strong <111> texture were tested. The measured Young moduli agreed with those measured on bulk crystals, but the measured Poisson ratios were low, most likely due to slight transverse folding of the film that developed during the test.


2021 ◽  
Author(s):  
Victor Malgras ◽  
Joel Henzie ◽  
Yoshitaka Matsushita ◽  
Yoshiyuki Sugahara ◽  
Yusuke Yamauchi

Thin films are typically bound to their substrate, limiting their integration on rough, porous, curved or chemically/thermally sensitive surfaces. Instead of employing tedious and expensive back-etching processes, certain chemical routes...


RSC Advances ◽  
2014 ◽  
Vol 4 (109) ◽  
pp. 63941-63945 ◽  
Author(s):  
Mei-Ling Wu ◽  
Jing Li ◽  
Li-Jun Wan ◽  
Dong Wang

A facile way to fabricate robust free-standing PS-b-PMMA thin films with perpendicularly orientated microdomains on monolayer graphene is reported.


2007 ◽  
Vol 329 ◽  
pp. 551-556
Author(s):  
Xiao Gang Jian ◽  
L.D. Shi ◽  
Ming Chen ◽  
Fang Hong Sun

Adhesion properties of diamond thin films are essential to their performance in technical applications. To obtain the adhesive strength precisely and quantitatively has been the frontier issue to the related scientists and engineers. In this paper, a new experimental equipment for blister tests was designed purposely and fabricated considering related influencing facts. A free-standing window of diamond thin film with the support of silicon wafer was obtained by the aid of photolithography and anisotropic wet etching technology so as to improve the precision of quantitative adhesion measures of diamond films. The mechanics for calculating the quantitative driving force of blister-induced delamination of diamond thin film is presented, which is on base of intensive modeling and simulation. The laser interferometer measurement with fine solution was used to pick up dynamic signals of diamond thin film bulge deformation in micrometer scale and the relationship demonstration of stress to strain of the diamond thin film was available, as a consequence, the adhesive strength could be obtained precisely and quantitatively by the valid model. The paper confirms the accessibility to precise quantitative adhesion measures of diamond films and the results will be beneficial to wide application of diamond thin films in the related fields.


2016 ◽  
Vol 40 (3) ◽  
pp. 2619-2627 ◽  
Author(s):  
Shrikant S. Raut ◽  
Babasaheb R. Sankapal

Fe2O3/MWCNTs hybrid thin film exhibits superior electrochemical supercapacitor behaviour in terms of specific capacitance, energy density and power density than the individual Fe2O3 and MWCNTs thin films.


ChemPhysChem ◽  
2017 ◽  
Vol 18 (9) ◽  
pp. 1061-1068 ◽  
Author(s):  
Jacob Johny ◽  
Selene Sepulveda-Guzman ◽  
Bindu Krishnan ◽  
David A. Avellaneda ◽  
Josue A. Aguilar Martinez ◽  
...  

2007 ◽  
Vol 352 ◽  
pp. 315-318 ◽  
Author(s):  
Akihiko Ito ◽  
Hiroshi Masumoto ◽  
Takashi Goto

Epitaxial BaRuO3 (BRO) and CaRuO3 (CRO) thin films were prepared on (001), (110) and (111) SrTiO3 (STO) single-crystal substrates by laser ablation, and their microstructures and anisotropy of electrical conductivity were investigated. The (205) (104), (110) and (009) oriented BRO thin films, and (001), (110) and (110) oriented CRO thin films were grown epitaxially on (001), (110) and (111) STO substrates with in-plain orientation, respectively. The (009) BRO thin film and (001) CRO thin film has a flat surface result from a good lattice matching to STO substrates. The (205) (104) BRO thin film and (111) CRO thin film exhibited orthogonal- and hexagonal-shaped texture, respectively. The (110) BRO thin film and (110) CRO thin film showed an island growth due to (110) surface feature of cubic perovskite structure. Epitaxial BRO and CRO thin films have a high electrical conductivity with a metallic conduction, the (111) CRO thin films exhibited the highest conductivity of 1.4×105 S·m-1.


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