Elementary molecular processes that govern the chemical stimulation of a polyurethane-based shape memory polymer

Shen, Yucen; Dumlu, Hakan; Eggeler, Gunther; Neuking, K.

doi:10.1016/j.polymer.2023.126070

Cited by 2 publications

(11 citation statements)

References 25 publications

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“…diffusion in polymers [1,2] is combined with shape memory polymer (SMP) technology [3,4]. In previous work, the chemical actuation of the shape memory effect was studied [5][6][7][8]. Chemical actuation was triggered by the diffusion of small molecules into a SMP.…”

Section: Background and Scientific Objectivesmentioning

confidence: 99%

“…As a polymer, a polyetherbased polyurethane SMP with the tradename ESTANE ETE 75DT3 (abbreviation used throughout the present work: SMP-E) was studied. In a recent study, we considered the three alcohols of methanol, ethanol and 1-propanol and identified the molecular scenario that governs chemical actuation [7]. In our present study, we take a closer look at the interaction of the three aliphatic alcohols with SMP-E, comparing their diffusion coefficients and exploring their diffusion path in a polymer morphology; this can be considered to consist of two phases: one providing the entropy elasticity (phase entropy elastic (EE)) and the other acting as a molecular switch (phase MS) [7].…”

Section: Background and Scientific Objectivesmentioning

confidence: 99%

“…In a recent study, we considered the three alcohols of methanol, ethanol and 1-propanol and identified the molecular scenario that governs chemical actuation [7]. In our present study, we take a closer look at the interaction of the three aliphatic alcohols with SMP-E, comparing their diffusion coefficients and exploring their diffusion path in a polymer morphology; this can be considered to consist of two phases: one providing the entropy elasticity (phase entropy elastic (EE)) and the other acting as a molecular switch (phase MS) [7]. We are interested in how the diffusion of small molecules into SMP can trigger shape recovery and compare the kinetics of diffusion with the kinetics of shape recovery.…”

Section: Background and Scientific Objectivesmentioning

confidence: 99%

“…Second, we used small angle x-ray scattering (SAXS) to find out how the diffusion of the three alcohols in the polymer affects the morphology of its two phases. Finally, we compared the diffusion of the three alcohols in SMP-E with previous actuation kinetics from [7].…”

Section: Background and Scientific Objectivesmentioning

confidence: 99%

“…L is the total size of one characteristic conglomerate and coincides with the x-value of the second first local maximum. Figure 2 shows a schematic drawing of the morphology with the red color for EE and blue for MS (same color coding as in the schematic drawing in figure 1 of [7]).…”

Section: Small Angle X-ray Scattering For Polymer Morphologiesmentioning

confidence: 99%

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Diffusion of small-size aliphatic alcohols and the chemical actuation of shape memory polyurethane

Shen,

Dumlu,

Varnik

et al. 2024

Smart Mater. Struct.

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Three types of aliphatic alcohols (methanol, ethanol, and 1-propanol) are used to actuate a programmed ESTANE ETE 75DT3 (abb. SMP-E), a polyether-based polyurethane shape memory polymer (SMP). In this paper, we analyze the diffusion behavior of these small molecules in SMP E and the relationship between the solvent diffusion and shape recovery using a weight gain study and small-angle x-ray scattering (SAXS). From the results, all three alcohols show behavior similar to Fickian diffusion in SMP-E. During the diffusion process, the molecular switch of thermoplastic SMP-E transforms from the glassy state to the rubber like state depending on the time-dependent local alcohol concentration. The diffusion of small molecules enhances shape recovery and the related evolution of the polymer structure. As a feedback effect, the rate of diffusion changes as small molecules penetrate into the sample. To study this issue, we used three methods to determine the diffusion coefficients at short, intermediate and long times. The data on short time diffusion reflects the glassy state of the sample. The intermediate times correspond to 50% solvent saturation, where the shape recovery is nearly completed. The long-time analysis, on the other hand, provides an average diffusion coefficient for the entire process. The SAXS results show the diffusion path and provide evidence that the alcohol molecules equally diffuse into both molecular switch (MS) and entropy elastic component (EE) phase of SMP E.

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Section: Background and Scientific Objectivesmentioning

confidence: 99%

Section: Background and Scientific Objectivesmentioning

confidence: 99%

Section: Background and Scientific Objectivesmentioning

confidence: 99%

Section: Background and Scientific Objectivesmentioning

confidence: 99%

Section: Small Angle X-ray Scattering For Polymer Morphologiesmentioning

confidence: 99%

See 3 more Smart Citations

Diffusion of small-size aliphatic alcohols and the chemical actuation of shape memory polyurethane

Shen,

Dumlu,

Varnik

et al. 2024

Smart Mater. Struct.

Self Cite

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A wide angle x-ray diffraction (WAXD) study of thermal and chemical actuation of a shape memory polymer

Shen,

Dumlu,

Eggeler

et al. 2024

Smart Mater. Struct.

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The one way effect (1WE) of the shape memory polymer ESTANE ETE 75DT3 (abbreviation: SMP-E) can be chemically triggered by exposure to methanol, ethanol, and 1 propanol. The present study uses wide angle X-ray diffraction to confirm that programming induces oriented structure in an initially amorphous state. During subsequent shape recovery the sharp diffraction intensity peaks of the programmed state weaken, and oriented amorphous structure is partly lost. This corresponds to the finding that initial shapes cannot be fully recovered. The present work shows that the uptake of small alcohol molecules not only triggers shape recovery but also weakens intermolecular bonds, which results in strength decreasing. From the alcohol concentrations that were measured by weight gain studies, it can be concluded that the key parameter that governs the mechanical and functional behavior of SMP-E is the number of C-atoms that the SMP-E takes up. It is shown that thermal shape recovery is more effective than chemical shape recovery. Chemically triggered shape recovery can be used to lift small end loads corresponding to stresses of up to 1 MPa. The results are discussed in the light of previous work published in the literature.

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Elementary molecular processes that govern the chemical stimulation of a polyurethane-based shape memory polymer

Cited by 2 publications

References 25 publications

Diffusion of small-size aliphatic alcohols and the chemical actuation of shape memory polyurethane

Diffusion of small-size aliphatic alcohols and the chemical actuation of shape memory polyurethane

A wide angle x-ray diffraction (WAXD) study of thermal and chemical actuation of a shape memory polymer

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