Investigation of bifurcated hydrogen bonds within the thermotropic liquid crystalline polyurethanes

Lin, Chien Kung; Kuo, Jui‐Chao; Chen, Chuh Yung; Fang, Jiali

doi:10.1016/j.polymer.2011.11.009

Cited by 15 publications

(9 citation statements)

References 29 publications

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“…[1][2][3][4][5] As such, it should be mentioned that the hydrogen bond is not only a feasible model of non-bonded interaction, [6][7][8][9][10][11][12][13] but its properties play a crucial role in studies of chemistry, biology and physics, [14][15][16][17][18][19][20][21][22][23][24][25][26][27] and thereby ascribe it as one of the most important interactions of nature. Moreover, the origin of the hydrogen bond is a singular topic and its application is mightily useful, such as for example in engineering, 28 medicinal chemistry with drug design, [29][30][31] polymers, [32][33][34][35] macromolecular research, [36][37][38] understanding of biochemical processes [39][40][41][42] such as enzymatic and organometallic catalysis, 43,44 synthesis, [45][46][47] molecular recognition, …”

Section: Introductionmentioning

confidence: 99%

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Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H^−δ⋯H^+δdihydrogen bonds

Oliveira

2013

Phys. Chem. Chem. Phys.

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In this paper, the intermolecular structural study asserted by the vibrational analysis in the stretch frequencies of hydrogen bonds (π···H) and dihydrogen bonds (H(-δ)···H(+δ)) have definitively been revisited by means of calculations carried out by Density Functional Theory (DFT) and topological parameters derived from the classic treatise of the Quantum Theory of Atoms in Molecules (QTAIM). As a matter of fact the π···H hydrogen bond is formed between the hydrofluoric acid and the C≡C bond of the acetylene, but the QTAIM calculations revealed a distortion in this interaction due to the formation of the ternary complex C(2)H(2)···2(HF). Although the π bonds of ethylene (C(2)H(4)), propylene (C(2)H(3)(CH(3))), and t-butylene (C(2)H(2)(CH(3))(2)) are considered proton acceptors, two hydrogen-bond types--π···H and C···H--can be observed. Over and above the analysis of the π hydrogen bonds, theoretical arguments also were used to discuss the red-shifts in the stretch frequencies of the binary dihydrogen complexes formed by BeH(2)···HX with X = F, Cl, CN, and CCH. Although a vibrational blue-shift in the stretch frequency of the H-C bond of HCF(3) due to the formation of the BeH(2)···HCF(3) dihydrogen complex was obtained, unmistakable red-shifts were detected in LiH···HCF(3), MgH(2)···HCF(3), and NaH···HCF(3). Moreover, the alkali-halogen bonds were identified in relation to the formation of the trimolecular systems NaH···2(HCF(3)) and NaH···2(HCCl(3)). At last, theoretical calculations and QTAIM molecular integrations were used to study a novel class of dihydrogen-bonded complexes (mC(2)H(5)(+)···nMgH(2) with m = 1 or 2 and n = 1 or 2) based in the insight that MgH(2) can bind with the non-localized hydrogen H(+δ) of the ethyl cation (C(2)H(5)(+)). In an overview, QTAIM calculations were applied to evaluate the molecular topography, charge density, as well as to interpret the shifted frequencies either to red or blue caused by the formation of the hydrogen bonds and dihydrogen bonds.

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Section: Introductionmentioning

confidence: 99%

“…Fig 35. Illustration of the relief map of the electronic density of the LiHÁ Á ÁHCF 3 dihydrogen complex.…”

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confidence: 99%

Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H^−δ⋯H^+δdihydrogen bonds

Oliveira

2013

Phys. Chem. Chem. Phys.

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“…O¼C. The 'bifurcated' C¼O stretching vibration suggests that the C¼O groups are mostly hydrogen bonded [37]. Both the shift of the N -H and C¼O stretching vibration to low wavenumbers indicates abundant hydrogen bonding in the SRF.…”

Section: Resultsmentioning

confidence: 99%

Healable thermoset polymer composite embedded with stimuli-responsive fibres

Meng

2012

J. R. Soc. Interface.

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Severe wounds in biological systems such as human skin cannot heal themselves, unless they are first stitched together. Healing of macroscopic damage in thermoset polymer composites faces a similar challenge. Stimuli-responsive shape-changing polymeric fibres with outstanding mechanical properties embedded in polymers may be able to close macro-cracks automatically upon stimulation such as heating. Here, a stimuli-responsive fibre (SRF) with outstanding mechanical properties and supercontraction capability was fabricated for the purpose of healing macroscopic damage. The SRFs and thermoplastic particles (TPs) were incorporated into regular thermosetting epoxy for repeatedly healing macroscopic damages. The system works by mimicking self-healing of biological systems such as human skin, close (stitch) then heal, i.e. close the macroscopic crack through the thermal-induced supercontraction of the SRFs, and bond the closed crack through melting and diffusing of TPs at the crack interface. The healing efficiency determined using tapered double-cantilever beam specimens was 94 per cent. The self-healing process was reasonably repeatable.

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“…The three curves are in line with the characteristic peaks of waterborne polyurethane. The band located at 3321 cm −1 corresponds to the N−H stretching vibration and the band at 1531 cm −1 is assigned to the N–H in-plane bending vibration [ 18 , 19 ]. The absorption bands at 1460 and 1360 cm −1 are assigned to the –CH 2 – bending vibrations.…”

Section: Resultsmentioning

confidence: 99%

Preparation and Properties of Self-Healing Waterborne Polyurethane Based on Dynamic Disulfide Bond

Jiang

2021

Polymers

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A self-healing waterborne polyurethane (WPU) materials containing dynamic disulfide (SS) bond was prepared by introducing SS bond into polymer materials. The zeta potential revealed that all the synthesized WPU emulsions displayed excellent stability, and the particle size of them was about 100 nm. The characteristic peaks of N-H and S-S in urethane were verified by FTIR, and the chemical environment of all elements were confirmed by the XPS test. Furthermore, the tensile strength, self-healing process and self-healing efficiency of the materials were quantitatively evaluated by tensile measurements. The results showed that the self-healing efficiency could reach 96.14% when the sample was heat treated at 70 °C for 4 h. In addition, the material also showed a good reprocessing performance, and the tensile strength of the reprocessed film was 3.39 MPa.

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Investigation of bifurcated hydrogen bonds within the thermotropic liquid crystalline polyurethanes

Cited by 15 publications

References 29 publications

Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H^−δ⋯H^+δdihydrogen bonds

Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H^−δ⋯H^+δdihydrogen bonds

Healable thermoset polymer composite embedded with stimuli-responsive fibres

Preparation and Properties of Self-Healing Waterborne Polyurethane Based on Dynamic Disulfide Bond

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Investigation of bifurcated hydrogen bonds within the thermotropic liquid crystalline polyurethanes

Cited by 15 publications

References 29 publications

Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H−δ⋯H+δdihydrogen bonds

Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H−δ⋯H+δdihydrogen bonds

Healable thermoset polymer composite embedded with stimuli-responsive fibres

Preparation and Properties of Self-Healing Waterborne Polyurethane Based on Dynamic Disulfide Bond

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Product

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Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H^−δ⋯H^+δdihydrogen bonds

Structure, energy, vibrational spectrum, and Bader's analysis of π⋯H hydrogen bonds and H^−δ⋯H^+δdihydrogen bonds