Surface alteration implications on potential use of semi-alicyclic polyimide as biomedical materials

Barzic, Andreea Irina; Albu, Raluca Marinica; Stoica, Iuliana

doi:10.1016/j.apsusc.2020.148377

Cited by 11 publications

(5 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As previously reported in our studies [11,17,18,20,22,23,43], the surfaces of the polyimide samples, whose synthesis is based on EPI, are uniform, homogeneous, presenting the same morphological characteristics in all directions (morphologically isotropic), and with very low roughness, of a few nanometers. Mechanical surface treatments, such as stretching and friction with textiles, can alter these characteristics by inducing the orientation of the morphological features in a certain direction and thus the appearance of the anisotropy (as observed in Figures 6 and 7).…”

Section: Morphological Analysissupporting

confidence: 79%

“…In recent works, we showed that the use of cycloaliphatic dianhydrides in the PI synthesis leads to transparent materials, with high glass transition temperature, good dimensional stability, and appropriate adhesion with the LCs [9,[17][18][19][20][21]. Moreover, such partially aliphatic PIs have a smooth surface and their morphology can be modified by dynamic plowing lithography [22], rubbing [9,11,23], or by imprinting the banded texture of a lyotropic polymer [24,25].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

New Strategy for Inducing Surface Anisotropy in Polyimide Films for Nematics Orientation in Display Applications

Epure

Stoica²,

Albu³

et al. 2021

Nanomaterials

Self Cite

View full text Add to dashboard Cite

The operability of liquid crystal displays is strongly impacted by the orientation aspects of nematics, which in turn are affected by the alignment layer surface features. In this work, two polyimide (PI) structures are obtained based on a cycloaliphatic dianhydride and aromatic or aliphatic diamines with distinct flexibility. The attained PI films have high transmittance (T) for visible radiations, i.e., at 550 nm T > 80%. Here, a novel strategy for creating surface anisotropy in the samples that combines rubbing with a cloth and stretching via pressing is reported. Birefringence and atomic force microscopy (AFM) scans reveal that the generated orientation of the chains is affected by the chemical structure of the polymer and order of the steps involved in the surface treatment. Molecular modeling computations and wettability tests show that the PI structure and produced surface topography are competitive factors, which are impacting the intensity of the interactions with the nematic liquid crystals. The achieved results are of great relevance for designing of reliable display devices with improved uniform orientation of liquid crystals.

show abstract

Section: Morphological Analysissupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

New Strategy for Inducing Surface Anisotropy in Polyimide Films for Nematics Orientation in Display Applications

Epure

Stoica²,

Albu³

et al. 2021

Nanomaterials

Self Cite

View full text Add to dashboard Cite

show abstract

“…The nanoscale is to be considered for interactions with proteins and cell adhesion, the microscale involves 1–10 μm range and is important for mineralization-implant interfaces, while the macroscale looks at the millimeter to tens of micrometer range and is more relevant to the context of an overall implant rather than an individual cell level . Features produced by mechanical surface roughening may include cracks, grooves, and pits among other surface topographies − with resolution or scale determined by the process chosen. For instance, the feature size determined by sand blasting will depend on the particle size used, while water jet peening relies on the input pressure applied .…”

Section: Fabrication Of Micro- and Nanotopographic Surfaces For Cell ...mentioning

confidence: 99%

The Bumpy Road to Stem Cell Therapies: Rational Design of Surface Topographies to Dictate Stem Cell Mechanotransduction and Fate

Carthew

Taylor

Garcia-Cruz

et al. 2022

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Cells sense and respond to a variety of physical cues from their surrounding microenvironment, and these are interpreted through mechanotransductive processes to inform their behavior. These mechanisms have particular relevance to stem cells, where control of stem cell proliferation, potency, and differentiation is key to their successful application in regenerative medicine. It is increasingly recognized that surface micro- and nanotopographies influence stem cell behavior and may represent a powerful tool with which to direct the morphology and fate of stem cells. Current progress toward this goal has been driven by combined advances in fabrication technologies and cell biology. Here, the capacity to generate precisely defined micro- and nanoscale topographies has facilitated the studies that provide knowledge of the mechanotransducive processes that govern the cellular response as well as knowledge of the specific features that can drive cells toward a defined differentiation outcome. However, the path forward is not fully defined, and the “bumpy road” that lays ahead must be crossed before the full potential of these approaches can be fully exploited. This review focuses on the challenges and opportunities in applying micro- and nanotopographies to dictate stem cell fate for regenerative medicine. Here, key techniques used to produce topographic features are reviewed, such as photolithography, block copolymer lithography, electron beam lithography, nanoimprint lithography, soft lithography, scanning probe lithography, colloidal lithography, electrospinning, and surface roughening, alongside their advantages and disadvantages. The biological impacts of surface topographies are then discussed, including the current understanding of the mechanotransductive mechanisms by which these cues are interpreted by the cells, as well as the specific effects of surface topographies on cell differentiation and fate. Finally, considerations in translating these technologies and their future prospects are evaluated.

show abstract

“…9,[22][23][24] Moreover, knowing that rubbing changes the isotropic topographical features of PI film into anisotropic ones, it was shown that it also produces distinct interfacial adhesion to liquids along and orthogonal to rubbing direction. 25 However, an aspect that was not investigated in the literature is the effect induced by the positioning of the textile fiber concerning rubbing direction on the resulted PI film morphology and wettability. The bending of the main chain.…”

Section: Introductionmentioning

confidence: 99%

Alignment layers based on poly(oxadiazole‐naphthylimide)s: New aspects on tuning anisotropy of the surface morphology and adhesion via rubbing

Stoica¹,

Barzic²,

Albu³

et al. 2021

Polymers for Advanced Techs

Self Cite

View full text Add to dashboard Cite

Two poly(oxadiazole-naphthylimide) films are prepared and characterized to elucidate their suitability as alignment layers for nematics in display devices. First, rheological behavior is analyzed to establish in correlation with molecular modeling the optimal conditions of solution shearing to obtain uniform films by spin coating. Second, the polymer foils are subjected to rubbing with cellulose diacetate cloth to induce surface anisotropy required for nematic orientation. Novel insights are extracted here by studying the effect induced by the positioning of the textile fiber parallel/orthogonal to the rubbing direction on the induced polymer morphology through atomic force microscopy. The balance between the isotropic and anisotropic characters of the surface morphology of the unrubbed and rubbed polyimide (PI) samples is evaluated by Fourier spectrum integrated into polar coordinates and autocorrelation function analysis. The involvement of the created surface features on the anisotropy of the interfacial PI/nematic adhesion is further investigated. The qualitative orientation ability of the surface textured samples is evaluated revealing that both PI chain flexibility and fiber positioning are paramount for attaining uniform orientation of the nematic.

show abstract

Surface alteration implications on potential use of semi-alicyclic polyimide as biomedical materials

Cited by 11 publications

References 58 publications

New Strategy for Inducing Surface Anisotropy in Polyimide Films for Nematics Orientation in Display Applications

New Strategy for Inducing Surface Anisotropy in Polyimide Films for Nematics Orientation in Display Applications

The Bumpy Road to Stem Cell Therapies: Rational Design of Surface Topographies to Dictate Stem Cell Mechanotransduction and Fate

Alignment layers based on poly(oxadiazole‐naphthylimide)s: New aspects on tuning anisotropy of the surface morphology and adhesion via rubbing

Contact Info

Product

Resources

About