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A new method for measuring the spatial distribution of combined polarization and space charges in poled polymer electrets has been developed. The technique, called the laser-intensity-modulation method (LIMM), is based upon measurement of the pyroelectric current generated by the electret when it is heated with a laser beam which is intensity-modulated at frequencies varying from 200 to 2500 Hz. A special analytical technique is used to transform the current-frequency measurements to spatial distributions. The method gives high resolution and is very stable with respect to measurement errors. The technique can be easily implemented in a laboratory with conventional equipment. The advantages and limitations of LIMM are illustrated by means of calculations based upon simulated data. Experimental results on a number of laboratory and commercially poled samples are presented.

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Reconstituted collagen membranes (thickness 20–40 microns), used in periodontal guided tissue regeneration, were prepared by solubilization of bovine serosa and bovine tendon using an alkaline treatment and by solubilization of bovine serosa in acetic acid. Dielectric properties of these materials were determined in the frequency range of 10−5−106 Hz (poling temperature = 313 K, poling time = 3 h, E = 107 V/m), using a General Radio Bridge system (high frequencies) and a discharge current technique (low frequencies). The true pyroelectric coefficient p(T) was determined for these materials by a direct method over an appropriate temperature range. Their magnitude appear to be in the range of 10−4 to 10−5 C/m2 K−1, which is considerably higher than that of the ferroelectric poly(vinylidene fluoride) (PVDF) and its copolymer vinylidene fluoride‐trifluorethylene (VDF‐TrFE).