“…Besides, after the highest pressure application at 150 MPa, a partial PDA red phase appeared without UV irradiation which was not observed with other pellets pressed up to 100 MPa (Figure d insets). It suggests that the high-pressure application might result in the localized random 1,2- or 1,4-polymerization, and it is also known that the high pressure leads to an increase in the mosaicity of the crystals, generating some mismatch between the monomer crystal lattices . Although its XRD pattern showed noticeable disappearance of peaks at 2θ of around 3.8 and 9.3°, the wide-angle region showed similar displacement of peaks with the pellets pressed at lower pressures.…”
Mechanoresponsive
diacetylenes (DAs) exhibiting a transition of crystalline orientation
from light-inert to light-active state upon applied force are reported.
Amide units are introduced to DAs where hydrogen bonding is utilized
to control intermolecular interactions. Application of external pressure
(2–150 MPa) to DAs results in an emergence of new crystal phases
with changing the d-spacing which possibly reduces
the reaction barrier. Accordingly, the dramatic crystalline transition
from “perfectly off” to “on” state to
undergo the light-induced topochemical polymerization of bulk DA crystals
is obtained. Subsequent UV irradiation at a wavelength of 254 nm enables
the polymerization of the pressed region, changing its color from
white to blue which suggests the selective formation of polydiacetylene
(PDA) polymorphs. In addition, by utilizing the mechanoresponsive
crystallinity with low-enough activation pressure, a new strategy
for PDA patterning is demonstrated based on the selective transfer
of information by means of force to a DA film. This phenomenon can
be applicable to a new nanoimprinting technique where no mechanical
deformation of resist materials but phase transition is induced by
the mold.
“…Besides, after the highest pressure application at 150 MPa, a partial PDA red phase appeared without UV irradiation which was not observed with other pellets pressed up to 100 MPa (Figure d insets). It suggests that the high-pressure application might result in the localized random 1,2- or 1,4-polymerization, and it is also known that the high pressure leads to an increase in the mosaicity of the crystals, generating some mismatch between the monomer crystal lattices . Although its XRD pattern showed noticeable disappearance of peaks at 2θ of around 3.8 and 9.3°, the wide-angle region showed similar displacement of peaks with the pellets pressed at lower pressures.…”
Mechanoresponsive
diacetylenes (DAs) exhibiting a transition of crystalline orientation
from light-inert to light-active state upon applied force are reported.
Amide units are introduced to DAs where hydrogen bonding is utilized
to control intermolecular interactions. Application of external pressure
(2–150 MPa) to DAs results in an emergence of new crystal phases
with changing the d-spacing which possibly reduces
the reaction barrier. Accordingly, the dramatic crystalline transition
from “perfectly off” to “on” state to
undergo the light-induced topochemical polymerization of bulk DA crystals
is obtained. Subsequent UV irradiation at a wavelength of 254 nm enables
the polymerization of the pressed region, changing its color from
white to blue which suggests the selective formation of polydiacetylene
(PDA) polymorphs. In addition, by utilizing the mechanoresponsive
crystallinity with low-enough activation pressure, a new strategy
for PDA patterning is demonstrated based on the selective transfer
of information by means of force to a DA film. This phenomenon can
be applicable to a new nanoimprinting technique where no mechanical
deformation of resist materials but phase transition is induced by
the mold.
“…Polymerization can also be initiated by UV or γ-ray irradiation or by heating. Pressure has been reported as a method for inducing polymerization of solid-state diynes in a relatively small number of cases. − 1 Alignment of Diynes for Topochemical Polymerization a a Optimal values for 1,4-polymerization are r = 4.9−5.0 Å, θ = 45°, and d = 3.5 Å …”
Section: Introductionmentioning
confidence: 99%
“…We have therefore returned to the cocrystals with pyridyl hosts 3 and 4 as sources of PIDA, examining pressure as a means to induce polymerization. There have been several reports of pressure-catalyzed polymerization of diynes. ,,− Pressure has been particularly useful in cases where steric bulk in the side groups impeded heat or light-induced polymerization. , At Stony Brook's COMPRES facility, we have access to equipment that can reach pressures as high as 10 GPa. We report here the successful polymerization of diiodobutadiyne upon subjecting the cocrystals to pressures of 0.3−10 GPa.…”
Section: Introductionmentioning
confidence: 99%
“…Pressure has been reported as a method for inducing polymerization of solid-state diynes in a relatively small number of cases. [7][8][9][10][11][12] Fowler and Lauher have extended the range of accessible poly(diacetylenes) by preparing host molecules such as 3 and 4 (Figure 1), which will form cocrystals with a variety of diynes. 13,14 In these cocrystals, the oxalamides of the host create a one-dimensional hydrogen-bonding network with a repeat distance of 4.9-5.1 Å, while the pyridine rings interact with the diyne guest, transmitting the repeat parameter to the diyne.…”
Section: Introductionmentioning
confidence: 99%
“…There have been several reports of pressure-catalyzed polymerization of diynes. 7,8,[24][25][26] Pressure has been particularly useful in cases where steric bulk in the side groups impeded heat or light-induced polymerization. 7,8 At Stony Brook's COMPRES facility, we have access to equipment that can reach pressures as high as 10 GPa.…”
Diiodobutadiyne forms cocrystals with bis(pyridyl)oxalamides in which the diyne alignment is near the ideal parameters for topochemical polymerization to the ordered conjugated polymer, poly(diiododiacetylene) (PIDA). Nonetheless, previous efforts to induce polymerization in these samples via heat or irradiation were unsuccessful. We report here the successful ordered polymerization of diiodobutadiyne in these cocrystals, by subjecting them to high external pressure (0.3-10 GPa). At the lower end of the pressure range, the samples contain primarily monomer, as demonstrated by X-ray diffraction studies, but some polymerization does occur, leading to a pronounced color change from colorless to blue and to the development of intense Raman peaks at 962, 1394, and 2055 cm-1, corresponding to the poly(diacetylene). At higher pressures, the samples turn black and contain primarily polymer, as determined by solid-state NMR and Raman spectroscopy. Both density functional theory calculations (B3LYP/LanL2DZ) and comparisons to authentic samples of PIDA have confirmed the data analysis.
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