Rapid Fabrication of Three-Dimensional Porous Films with Biomimetic Patterns by Natural Evaporation of Amphiphilic Polyacetylene Solutions under Ambient Conditions

Salhi, Fouad; Cheuk, Kevin Ka Leung; Sun, Qunhui; Lam, Jacky W. Y.; John, Alexandra; Li, Gao; Li, Bingshi; Luo, Jingdong; Chen, Junwu; Tang, Ben Zhong

doi:10.1166/jnn.2001.022

Cited by 18 publications

(7 citation statements)

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“…We then turned our attention to other transition-metal catalysts with better tolerance to polar groups. Organorhodium complexes are known to be effective in polymerizing PA monomers with functional groups in insertion mechanism, ,, and we thus checked whether these complexes could work for our Leu−PA monomers.…”

Section: Resultsmentioning

confidence: 99%

“…The amphiphilic polymers may emulate the behaviors of biopolymers, thus offering a simple artificial model system for the studies of complex natural systems. In our previous work, we attached pendants of l -valine (Val), an amino acid commonly found in proteins, to the backbone of poly(phenylacetylene) (PPA), the best-known photoconductive polyacetylene . The Val−PPA hybrids formed helical structures and self-assembled into biomimetic morphologies, in which hydrogen bonding was believed to play a vital role.…”

Section: Introductionmentioning

confidence: 99%

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Amino Acid-Containing Polyacetylenes: Synthesis, Hydrogen Bonding, Chirality Transcription, and Chain Helicity of Amphiphilic Poly(phenylacetylene)s Carryingl-Leucine Pendants

et al. 2003

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L-Leucine-phenylacetylene adducts 6 and 14 undergo self-association in concentrated solutions and heterocomplexation with solvent molecules through hydrogen bond formation. The adducts are polymerized by rhodium catalysts into poly(4-ethynylbenzoyl-L-leucine methyl ester) (1e) and poly-[11-(4-ethynylphenoxy)undecanoyl-L-leucine methyl ester] (2e), with the polymerizations of 6 producing polymers with high molecular weights (Mw up to 1.47 × 10 6 ) and high stereoregularity (Z content up to 100%) in high yields (up to 92%). The ester groups of "polyesters" 1e and 2e are selectively hydrolyzed under basic conditions to afford "polyacids" 1a and 2a carrying free leucine pendants. The polymers are thermally stable (up to ∼260 °C) and undergo Z-E isomerization at ∼200 °C. The chirality transcription from the L-leucine pendants induces the chain segments of polymers 1 to helically spiral predominantly in one preferred direction, while the helicity induction processes in 2 are interrupted by the relaxations of the long flexible spacers between the chiral pendants and the polyene backbones. The chiroptical properties of the amphiphilic polymers change with solvent. In nonpolar solvents, 1 shows high optical activities and strong Cotton effects, whose helical structures are stabilized by intra-and interchain hydrogen bonding. The chain helicity of the polymers decreases in polar solvents due to the partial breakage of the hydrogen bonds within and between the polymer strands. † An Area of Excellence (AoE) Scheme administrated by the University Grants Committee of Hong Kong.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Amino Acid-Containing Polyacetylenes: Synthesis, Hydrogen Bonding, Chirality Transcription, and Chain Helicity of Amphiphilic Poly(phenylacetylene)s Carryingl-Leucine Pendants

et al. 2003

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“…Noncovalent functionalization of MWCNTs with PPAs is harmless to the inherent mechanical properties of MWCNTs, thereby is helpful to enhance the mechanical strength of CS rods. Moreover, good biocompatibility and cytophilic property of PPAs have been verified by intentionally designed experiments (Salhi et al, 2001).…”

Section: Introductionmentioning

confidence: 87%

Chitosan rods reinforced by aligned multiwalled carbon nanotubes via magnetic-field-assistant in situ precipitation

Wang

Zhao

Fan

et al. 2011

Carbohydrate Polymers

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Chitosan (CS) rods are a good candidate as temporary mechanical supports in bone regeneration, however the bending strength and bending modulus should be improved to match commercially available devices used for bone fracture internal fixation. Poly(p-amino-phenylacetylene)/multi-walled carbon nanotubes (PaPA/MWCNTs) hybrids with superparamagnetic Fe 3 O 4 nanoparticles (Fe 3 O 4 @PaPA/MWCNTs) are applied to reinforce the CS rods. Fe 3 O 4 @PaPA/MWCNTs could be uniformly dispersed in CS solution and aligned by an external magnetic field, in the direction parallel to the axis of CS rod. This greatly helped to resist the bending stress, thus the bending strength and modulus of the reinforced CS rods are 124.6 MPa and 5.3 GPa, respectively; which are 34.8% and 29.3% stronger than pure CS rods. As a result, the magnetic-field-assisted in situ precipitation method offers one feasible route for the reinforcement of CS-based devices with nano-scaled one-dimensional additives such as MWCNTs. In addition, CS-based biomaterials containing Fe 3 O 4 @PaPA/MWCNTs could obviously promote MG63 cells proliferation, so CS rods modified with Fe 3 O 4 @PaPA/MWCNTs are good candidates for bone fracture internal fixation.

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“…Polyalkynes are the best-known conjugated macromolecules and have attracted much interest among scientists. A rich variety of polyalkynes has been prepared in the past decades, thanks to the enthusiastic synthetic efforts of polymer chemists. − The conjugated polymers exhibit an array of exotic properties, examples of which include photoconductivity, solvato- and thermochromisms, radiolysis, photo- and electroluminescence, optical nonlinearity, liquid crystallinity, helical chirality or optical activity, biomimetic environmental adaptability, and cell growth-stimulating capability .…”

Section: Introductionmentioning

confidence: 99%

Hyperbranched Organometallic Polymers: Synthesis and Properties of Poly(ferrocenylenesilyne)s

Sun

Peng

et al. 2003

Macromolecules

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A series of hyperbranched poly(ferrocenylenesilyne)s, [(η 5 -C5H4) 18)]}, was prepared in good isolation yields (up to 77 wt %) by one-pot coupling reactions of dilithioferrocene with trichlorosilanes. While the polymers with small R groups [1(1) and 1(V)] were partially soluble, those with long alkyl chains [1(m) with m g 8] were completely soluble and readily film forming. The polymers exhibited diagnostic solution properties of hyperbranched macromolecules; for example, 1(18) had a high absolute molecular weight (M w ) 5 × 10 5 Da) but a low intrinsic viscosity ([η] ) 0.02 dL/g). Spectroscopic analyses revealed that the polymers possessed rigid skeleton structures with extended conjugations, with their absorption spectra tailed into the infrared region (>700 nm). With an increase in the alkyl chain length, the polymer changed from glassy to rubbery state. The polymers lost little of their weights when heated to ∼400 °C but ceramized when pyrolyzed at higher temperatures, with ceramization yield increasing with a decrease in the alkyl chain length. Sintering 1(1) and 1(V) in 700-1200 °C produced ceramics in ∼50% yields. Higher temperature pyrolyses favored the formation of ceramics with bigger inorganic nanoclusters and better magnetic performances. The ceramic prepared from the calcination of 1(1) at 1200 °C contained large iron silicide nanocrystals and exhibited high magnetizability (up to ∼51 emu/g) but near-zero remanence and coercivity. This ceramic is thus an outstanding soft ferromagnet with a high magnetic susceptibility and practically nil hysteresis loss.

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Rapid Fabrication of Three-Dimensional Porous Films with Biomimetic Patterns by Natural Evaporation of Amphiphilic Polyacetylene Solutions under Ambient Conditions

Cited by 18 publications

References 0 publications

Amino Acid-Containing Polyacetylenes: Synthesis, Hydrogen Bonding, Chirality Transcription, and Chain Helicity of Amphiphilic Poly(phenylacetylene)s Carryingl-Leucine Pendants

Amino Acid-Containing Polyacetylenes: Synthesis, Hydrogen Bonding, Chirality Transcription, and Chain Helicity of Amphiphilic Poly(phenylacetylene)s Carryingl-Leucine Pendants

Chitosan rods reinforced by aligned multiwalled carbon nanotubes via magnetic-field-assistant in situ precipitation

Hyperbranched Organometallic Polymers: Synthesis and Properties of Poly(ferrocenylenesilyne)s

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