A modified fabrication process based on initiated chemical vapor deposition (iCVD) has been developed for producing ultrathin and uniform polymer films. This so-called "closed batch" (CB) iCVD process provides fine-tuning of the thickness and deposition rate of polymeric materials while using significantly less reactant material than the conventional continuous flow (CF) iCVD process. Four different polymers, poly(N-isopropylacrylamide), poly(trivinyltrimethylcyclotrisiloxane), poly-(1H,1H,2H,2H-perfluorodecyl acrylate), and poly(epsilon-caprolactone), were synthesized by both CB and traditional CF iCVD. The resulting CB iCVD polymers are functionally identical to CF iCVD and solution-polymerized materials. Additionally, the new CB process retains the desirable ability to achieve conformal coverage over microstructures. Ultrathin (<30 nm) films can be controllably and reproducibly deposited; no prior optimization process is required to obtain excellent film thickness uniformity. The CB iCVD films are also extremely smooth, exhibiting RMS roughness values between 0.4 and 0.7 nm. Use of the CB process improves reaction yield by factors of 10-200 for the four different film chemistries and decreases material cost per 100 nm of film by 1-2 orders of magnitude.