Many nations are involved in polar research. In Antarctica, more than 40 countries operate research stations across the continent. Some of the countries producing the most Antarctic science, I would say, are (not in a particular order) Germany, United Kingdom, United States, and Australia which all have very large and active Antarctic research programs and infrastructure. However, there are a lot of other countries with dedicated Antarctic research programs and vessels too like South Korea, France, Italy, etc.

There are some private endeavors in polar research still, despite the expense! Some companies like National Geographic, the Great Barrier Reef Foundation and others support Antarctic research. There are also a lot of efforts in Antarctica for citizen science in collaboration with tourist ships which are also a private source of "funding" for research.