US4393093A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of high gamma (α)phase poly(vinylidene fluoride) piezoelectric materials
Assignee: Arkema Inc
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Filing: 1981-06-12
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Granted: 1983-07-12
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Expires: 2001-06-12
Abstract
Abstract The piezoelectric and pyroelectric activity of vinylidene fluoride polymers is enhanced by treating the polymers with a glow discharge at a reduced pressure. The treatment is believed to convert a portion of the α phase crystal content of the polymers to the γ phase. Piezoelectric and pyroelectric elements are formed by metallizing a film of the treated polymer and poling the metallized film.
Inventors
- 👤 Oliver S. Sprout, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:34
CPC Classifications
B; B29; B29C; B29C59/00; B29C59/14; H; H10; H10N; H10N30/00; H10N30/01; H10N30/09; H10N30/098
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
60 words
A process for increasing the piezoelectric activity of a vinylidene fluoride polymer containing an α crystalline phase and having an α/β ratio of at least about 0.05 comprising treating the polymer with a glow discharge at reduced pressure to convert a portion of the α crystalline phase to γ crystalline phase and then poling the polymer in an electric field.
Claim 2
Dependent Claim
60 words
A process for increasing the piezoelectric activity of a vinylidene fluoride polymer containing an α crystalline phase and having an α/β ratio of at least about 0.05 comprising treating the polymer with a glow discharge at reduced pressure to convert a portion of the α crystalline phase to γ crystalline phase and then poling the polymer in an electric field.
Claim 3
Dependent Claim
16 words
The process of claim 1 including the step of coating the polymer with a metal film.
Claim 4
Dependent Claim
18 words
The process of claim 2 wherein the treating and coating is carried out in the same vacuum chamber.
Claim 5
Dependent Claim
25 words
The process of claim 1 wherein the polymer is treated at a pressure of 0.01 to 2 torr for from at least about 3 minutes.
Claim 6
Dependent Claim
42 words
The process of claim 1 wherein the polymer is in the form of a film and, after the polymer is treated with the glow discharge, it is coated on each side with a metal film so as to form a piezoelectric element.
Claim 7
Dependent Claim
13 words
The process of claim 1 wherein the polymer is a poly(vinylidene fluoride) homopolymer.
Claim 8
Dependent Claim
16 words
The process of claim 1 wherein the the α/β ratio is from about 0.05 to 3.0.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-07-11 | 1987-01-10 | 1987-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-07-11 | 1991-01-10 | 1991-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-07-11 | 1995-01-10 | 1995-07-12 | $7700.00 | Window Closed / Lapsed |