Synthesis, characterization, and crystallization of biodegradable poly(ε-caprolactone)-poly(L-lactide) diblock copolymers

e-Polymers ◽  
2015 ◽  
Vol 15 (1) ◽  
pp. 15-23
Author(s):  
Song Luo ◽  
Xinyu Peng ◽  
Ying Chen ◽  
Ting Su ◽  
Jun Cao ◽  
...  
Keyword(s):  
Diblock Copolymers ◽  
Gel Permeation Chromatography ◽  
Copolymer Film ◽  
Force Microscopy ◽  
Molecular Weights ◽  
Atomic Force ◽  
Nuclear Magnetic Resonance Spectra ◽  
Biodegradable Poly ◽  
Obvious Phase Separation ◽  
Microscopy Images

AbstractThree diblock copolymers of PCL6k-PLLA2k, PCL6k-PLLA4k, and PCL6k-PLLA6k were prepared and their crystallization behaviors were investigated. The molecular weights of the copolymers calculated from 1H nuclear magnetic resonance spectra were equivalent to the designed molecular weights. The gel permeation chromatography spectra of the copolymers showed one peak, which revealed that the copolymers were monodisperse. The crystallization capability of poly(ε-caprolactone) (PCL) decreased and that of poly(L-lactide) (PLLA) increased when the molecular weight of the PLLA block was increased from 2k to 6k. PCL spherulites in the PCL6k-PLLA2k copolymer film were smaller than those in PCL6k-PLLA4k or PCL6k-PLLA6k copolymer film. PCL spherulites in the PCL6k-PLLA2k copolymer film grew fastest within all three diblock copolymers. An obvious phase separation phenomenon was observed on the surface of PCL6k-PLLA6k copolymer film in atomic force microscopy images.

Synthesis and Characterization of Linear Polymers for Non-Linear Optics through Click Chemistry Route

2012 ◽  
Vol 584 ◽  
pp. 8-12 ◽  
Author(s):  
Balakrishna Kolli ◽  
Sarada P. Mishra ◽  
Mukesh P. Joshi ◽  
S. Raj Mohan ◽  
T.S. Dhami ◽  
...  
Keyword(s):  
Click Chemistry ◽  
Second Harmonic ◽  
Gel Permeation Chromatography ◽  
Linear Polymers ◽  
Linear Optics ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Molecular Weights ◽  
Non Linear Optics ◽  
Atomic Force

Click chemistry is used for synthesizing polymers for second order NLO study. The molecular weights found by gel-permeation chromatography (GPC), were in the range of 7000-55000 g/mol. Differential scanning calorimetry shows glass transition temperature (Tg) above 120 oC. From electronic spectra order parameter of the poled films were calculated to be 0.1-0.5. The change in surface morphology after poling was checked by atomic force microscopy. By using a pulsed Nd:YAG laser (1064nm), the second harmonic generation (SHG) intensity was measured. The SHG intensity was also studied as a function of against temperature and time respectively.

scholarly journals Simulating noncontact atomic force microscopy images

2019 ◽  
Vol 3 (11) ◽  
Author(s):  
James R. Chelikowsky ◽  
Dingxin Fan ◽  
Alex J. Lee ◽  
Yuki Sakai
Keyword(s):  
Atomic Force Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Images

scholarly journals Corrosion Behavior and Mechanical Properties of a Nanocomposite Superhydrophobic Coating

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 652
Author(s):  
Divine Sebastian ◽  
Chun-Wei Yao ◽  
Lutfun Nipa ◽  
Ian Lian ◽  
Gary Twu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Nanocomposite Coating ◽  
Superhydrophobic Coating ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Images ◽  
Scanning Electron

In this work, a mechanically durable anticorrosion superhydrophobic coating is developed using a nanocomposite coating solution composed of silica nanoparticles and epoxy resin. The nanocomposite coating developed was tested for its superhydrophobic behavior using goniometry; surface morphology using scanning electron microscopy and atomic force microscopy; elemental composition using energy dispersive X-ray spectroscopy; corrosion resistance using atomic force microscopy; and potentiodynamic polarization measurements. The nanocomposite coating possesses hierarchical micro/nanostructures, according to the scanning electron microscopy images, and the presence of such structures was further confirmed by the atomic force microscopy images. The developed nanocomposite coating was found to be highly superhydrophobic as well as corrosion resistant, according to the results from static contact angle measurement and potentiodynamic polarization measurement, respectively. The abrasion resistance and mechanical durability of the nanocomposite coating were studied by abrasion tests, and the mechanical properties such as reduced modulus and Berkovich hardness were evaluated with the aid of nanoindentation tests.

scholarly journals Influence of Growth Temperature of the Nucleation Layer on the Growth of InP on Si (001)

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 823
Author(s):  
Shizheng Yang ◽  
Hongliang Lv ◽  
Likun Ai ◽  
Fangkun Tian ◽  
Silu Yan ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Wafer Level ◽  
X Ray Diffraction ◽  
Nucleation Layer ◽  
Force Microscopy ◽  
Gas Source ◽  
Atomic Force ◽  
Growth Method ◽  
Step Growth ◽  
Microscopy Images

InP layers grown on Si (001) were achieved by the two-step growth method using gas source molecular beam epitaxy. The effects of growth temperature of nucleation layer on InP/Si epitaxial growth were investigated systematically. Cross-section morphology, surface morphology and crystal quality were characterized by scanning electron microscope images, atomic force microscopy images, high-resolution X-ray diffraction (XRD), rocking curves and reciprocal space maps. The InP/Si interface and surface became smoother and the XRD peak intensity was stronger with the nucleation layer grown at 350 °C. The Results show that the growth temperature of InP nucleation layer can significantly affect the growth process of InP film, and the optimal temperature of InP nucleation layer is required to realize a high-quality wafer-level InP layers on Si (001).

scholarly journals Synthesis of amphiphilic ABA triblock oligomer via ATRP and its surface properties

2017 ◽  
Vol 95 (5) ◽  
pp. 605-611 ◽  
Author(s):  
Lei Wang ◽  
Shaoqing Wen ◽  
Zhanxiong Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Microphase Separation ◽  
Gel Permeation Chromatography ◽  
Contact Angles ◽  
Chemical Compositions ◽  
Water Contact ◽  
Force Microscopy ◽  
Atomic Force ◽  
Poly Ethylene ◽  
Magnetic Resonances

A series of novel amphiphilic ABA-type poly(tridecafluorooctylacrylate)-poly(ethylene glycol)-poly(tridecafluorooctylacrylate) (henceforth referred to as p-TDFA-PEG-p-TDFA) triblock oligomers were successfully synthesized via atom transfer radical polymerization (ATRP) using well-defined Br-PEG-Br as macroinitiator and copper as catalyst. The block oligomers were characterized by Fourier transform infrared (FTIR) spectroscopy and 1H and 19F nuclear magnetic resonances (NMR). Gel permeation chromatography (GPC) showed that the block oligomers have been obtained with narrow molecular weight distributions of 1.22–1.33. X-ray photoelectron spectroscopy (XPS) was carried out to confirm the attachment of p-TDFA-PEG-p-TDFA onto the silicon substrate, together with the chemical compositions of p-TDFA-PEG-p-TDFA. The wetabilities of the oligomer films were measured by water contact angles (CAs). Water CAs of p-TDFA-PEG-p-TDFA film were measured and their morphologies were tested by atomic force microscopy (AFM). The result showed that the CAs of the oligomer films, which possess fluoroalkyl groups assembled on the outer surface, increase after heating due to the migration of fluoroalkyl groups and the resulted microphase separation of the p-TDFA-PEG-p-TDFA.

A Scanning Force Microscopy Study of Block Copolymers Containing a Conjugated Segment

1997 ◽  
Vol 488 ◽  
Author(s):  
Ph. Leclère ◽  
R. Lazzaroni ◽  
V. Parente ◽  
B. François ◽  
J. L. Brédas
Keyword(s):  
Diblock Copolymers ◽  
Scanning Force Microscopy ◽  
Microscopy Study ◽  
Phase Detection ◽  
Force Microscopy ◽  
Atomic Force ◽  
Molecular Dynamics Calculations ◽  
Chain Composition ◽  
Scanning Force ◽  
Tapping Mode Afm

AbstractAtomic Force Microscopy (AFM) and related techniques are used to investigate the morphology of diblock copolymers. We focus on compounds containing a conjugated segment, polyparaphenylene, associated to a polymethylmethacrylate or a polystyrene block. The influence of the presence of the conjugated segment on the microdomain morphology is analyzed as a function of chain composition. Separate microdomains are observed on the surface of thin films by means of phase-detection imaging tapping-mode AFM. Their shape and size are interpreted in terms of molecular aggregation, with the help of molecular dynamics calculations.

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